Thermal treatment processes for spent hydroprocessing catalyst

ABSTRACT

A process to upgrade heavy oil and convert the heavy oil into lower boiling hydrocarbon products is provided. The process employs a catalyst slurry comprising catalyst particles with an average particle size ranging from 1 to 20 microns. In the upgrade process, spent slurry catalyst in heavy oil is generated as an effluent stream, which is subsequently recovered/separated from the heavy oil via membrane filtration. Residual hydrocarbons, i.e., heavy oil and solvent employed in the filtration for the heavy oil extraction are removed from the catalyst particles in a drying zone which employs at least two drying apparatuses to volatize residual hydrocarbons in the catalyst. Valuable metals can be recovered from catalyst particles for subsequent re-use in a catalyst synthesis unit, generating a fresh slurry catalyst.

RELATED APPLICATIONS

This application is a division of prior application Ser. No. 12/345,826filed Dec. 30, 2008.

BACKGROUND

As light oil reserves are gradually being depleted and the costs ofdevelopment (e.g., lifting, mining, and extraction) of heavy oilresources have increased, a need has arisen to develop novel upgradingtechnologies to convert heavy oils and bitumens into lighter products.With the advent of heavier crude feedstock, refiners are forced to usemore catalysts than before to upgrade the heavy oil and removecontaminants/sulfur from these feedstocks. These catalytic processesgenerate huge quantities of spent catalyst. With the increasing demandand market price for metal values and environmental awareness thereof,catalysts can serve as a secondary source for metal recovery.

In order to recycle/recover catalytic metals and provide a renewablesource for the metals, efforts have been made to extract metals fromspent catalysts generated from heavy oil upgrade processes, whether insupported or bulk catalyst form. Before catalytic metals can beextracted/recovered from spent catalysts, residual heavy oil fromhydroprocessing operations has first to be separated from the spentcatalysts. Effluent streams from heavy oil upgrade system typicallycontain unconverted heavy oil materials, heavier hydrocracked liquidproducts, slurry catalyst ranging from 3 to 50 wt. %, small amounts ofcoke, asphaltenes, etc. Conventional filtration processes may not besuitable to separate/recover slurry catalyst from high molecular weighthydrocarbon materials in the effluent streams as the unsupported finecatalyst may cause plugging or fouling of filters.

Membrane technology has long been used in removal of contaminants inenvironmental clean-up, wastewater treatment and water purification,particularly with the use of microfiltration, ultrafiltration,nanofiltration and reverse osmosis. Nanofiltration has more recentlybeen used to purify/remove impurities such as vanadium (in ppm amounts)from low boiling hydrocarbon mixtures boiling such as kerosene.

Heavy oil exposed to hydrocracking conditions is particularly difficultto extract/remove/separate from slurry catalyst. Conventional solventextraction and roasting methods in the prior art do not workparticularly well with slurry catalyst, leaving heavy oil behind withthe catalyst particle, thus creating problems in the downstream metalrecovery process (recovering valuable metals from spent catalyst). Somechemicals in the residual entrained oil in catalyst particles causefoaming issues during the metals recovery process and negatively impactany attempts at metals recovery using chemical extraction, pressureleaching, metal digestion/solubilization, crystallization, and orprecipitation methodologies.

The present invention relates to novel applications of membranetechnology in separating and/or extracting residual heavy oil from spentcatalyst particles generated from heavy oil upgrade operations, andsubsequently removing residual heavy oil from catalyst particulates toless than 0.5 wt. % in one embodiment.

SUMMARY

In one aspect, the invention relates to a system for separating heavyoil from catalyst particles is provided with a drying zone comprising atleast two drying stages, with the 2^(nd) drying stage for thevolatilization of organic matters, e.g., hydrocarbons such as solventand heavy oil, from the catalyst particles. In one embodiment, the firstdrying stage is a combined horizontal and vertical wiped-filmdryer/evaporator and the second stage is a rotary kiln dryer. In oneembodiment, the rotary kiln dryer is operated at a sufficiently hightemperature to volatize organic matters such as carboxylates bound tothe surface of the catalyst particles.

In yet another aspect, the invention relates to a process for separatingheavy oil from catalyst particles is provided. The process comprising:drying a composition containing comprising catalyst particles and 50 to90 wt. % hydrocarbons in a drying zone comprising at least two dryingstages, with the 2^(nd) drying stage for the volatilization of theorganic matters, e.g., solvent and heavy oil, from the catalystparticles; and removing the catalyst particles from the drying zone as adry powder.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

FIG. 1A is a cross-sectional view of a plate and frame filtration unit.

FIG. 1B is a partially developed view showing an embodiment of amembrane filtration system with a pleated membrane structure.

FIG. 1C is a schematic diagram of a membrane filtration system with atubular membrane filter.

FIG. 1D is a perspective view of a membrane system having a plurality oftubular/hollow membrane filters.

FIG. 1E is a perspective view of a membrane system in a spiral woundform.

FIG. 2 is a schematic diagram of a countercurrent sedimentationseparator with membrane channels arranged in parallel and two opposite(countercurrent) inflow streams into a receiving chamber.

FIG. 3 is a schematic diagram of a cross-flow sedimentation separatorwith membrane channels arranged in parallel, with an inflow stream onone side of the channels and an outlet (filtrate) stream at the oppositeside of the channels.

FIG. 4 is a block diagram of an embodiment of a deoiling operation.

FIG. 5 is a block diagram of another embodiment of a deoiling unit, witha concentration zone.

FIG. 6 is a block diagram showing a third embodiment of a deoiling unit,with a slurry concentration zone.

FIG. 7 is a block diagram showing another embodiment of a deoiling unit,employing a concentration zone as well as a slurry concentration zone.

FIG. 8 is a block diagram illustrating an embodiment of a membranefiltration system with multiple cross-flow filtration units.

FIG. 9 is a block diagram illustrating an embodiment of a membranefiltration system with a settling tank for solvent washing.

FIG. 10 is a block diagram illustrating an embodiment of a deoilingsystem with a membrane filtration zone and a two-staged drying zone,including a Combi dryer and a rotary kiln dryer.

FIG. 11 is a block diagram showing a recirculation operation in anembodiment employing dynamic filtration, e.g., a Vibratory ShearEnhanced Processing (V*SEP) unit.

FIG. 12 is a graph of a membrane study in an embodiment employingdynamic filtration, e.g., a V*SEP unit.

FIG. 13 is a graph of a pressure study in an embodiment employingdynamic filtration, e.g., a V*SEP unit.

FIG. 14 is a block diagram showing a batch operation employing dynamicfiltration, e.g., a V*SEP unit.

FIG. 15 is a graph of a diafiltration study in an embodiment employingdynamic filtration, e.g., a V*SEP unit.

FIG. 16 is a graph of particle size distribution in an embodimentemploying dynamic filtration, e.g., a V*SEP unit.

DETAILED DESCRIPTION

The following terms will be used throughout the specification and willhave the following meanings unless otherwise indicated.

“Average flux” refers to a time weighted average flux measured over aparticular concentration range.

“Batch concentration” refers to a dynamic filtration system, e.g., aVibratory Shear Enhanced Processing (V*SEP) machine configuration, wherea fixed amount of feed slurry is progressively concentrated by removalof permeate from the system. The concentrate from the system is returnedto a feed tank.

“Concentrate,” also known as “retentate,” refers to the portion ofslurry that does not permeate through a filter medium, e.g., a membrane.Stated otherwise, it is the portion of slurry which does not filterthrough the membrane.

“Concentration factor” refers to a ratio of feed flow rate toconcentrate flow rate.

“Cross-flow” filtration (or crossflow filtration or tangential flowfiltration (TFF)) refers to a filtration technique in which the feedstream flows (parallel or tangentially) along the surface of themembrane and the filtrate flows across the membrane. In cross-flowfiltration, typically only the material which is smaller than themembrane pore size passes through (across) the membrane as permeate orfiltrate, and everything else is retained on the feed side of themembrane as retentate or concentrate. In one embodiment of cross-flowfiltration, only a portion of the liquid in the solids-containing streampassing through the filter medium, i.e., the membrane. In contrast, inconventional filtration (dead-end filtration or normal filtration), theentire liquid portion of the slurry, rather than just a fraction of theliquid, is forced through the membrane, with most or all of the solidsretained by the membrane.

“Diafiltration” (DF) refers to a cross-flow filtration process wherein abuffer material, e.g., a solvent, is added into the feed stream and/orthe filtering process while filtrate is removed continuously from theprocess. In one embodiment of diafiltration, the process is used forpurifying retained large molecular weight species, increasing therecovery of low molecular weight species, buffer exchange and simplychanging the properties of a given solution. Diafiltration can be in theform of batch diafiltration or continuous diafiltration. In batch DF,the retentate is concentrated to the original volume or up to a certainconcentration of the slurry catalyst in the retentate. Once thisconcentration is reached, another volume of feed stream is added. Incontinuous DF, the volume of feed stream (solvent and catalyst slurry inheavy oil) is added to the filtration process at the same flow rate atwhich the filtrate and the concentrate are being removed. By thismethod, the volume of the fluid in the process can be kept constantwhile the smaller molecules, e.g., heavy oil in solvent, which canpermeate through the filter are washed away in the filtrate.

“Dynamic filtration” is an extension of cross-flow filtration, whereinthe filter medium is kept essentially free from plugging or fouling byrepelling particulate matter from the filter element and by disruptingthe formation of cake layers adjacent to the filter medium. Theseresults are accomplished by moving the material being filtered fastenough relative to the filtration medium to produce high shear rates aswell as high lift forces on the particles, such as by use of rotary,oscillating, reciprocating, or vibratory means. The shear at thefluid-filter medium interface is nearly independent of any crossflowfluid velocity, unlike tangential or crossflow filtration techniques(which suffer from other problems such as premature filter plugging dueto compound adsorption and large and nonuniform pressure dropsassociated with high tangential velocities alone the filter length,potentially causing backflow through the filtration medium and reducingfiltration).

“Microfiltration” refers to a membrane filtration process in whichhydrostatic pressure forces a liquid against a membrane, employingmicroporous membranes, i.e., membranes with pore size in the micronranges. Microfiltration can be in the form of cross-flow filtration,diafiltration, or dynamic filtration. In one embodiment, the membranesize is less than 100 nm. In another embodiment, the membrane sizeranges from 0.01 to 10 microns (10 to 10,000 nanometers). In oneembodiment, membranes of sufficient sizes are used for particles greaterthan or equal to 0.1 μm or 500,000 daltons in size or weight, areretained.

“Nanofiltration” refers to a membrane filtration process operates at alow to moderately high pressure (typically >4 bar, or in the range of50-450 psig), employing filters with very small pore sizes, i.e.,nanofilters with membranes having a pore size in the order of nanometers(1 nanometer=10 angstroms or 0.001 microns).

“Feed” may be used interchangeably with “feed slurry,” refers to amixture comprising heavy oil and spent slurry catalyst, offered forfiltration. The feed typically has suspended solids or molecules, whichare to be segregated from a clear filtrate and reduced in size, making aconcentrated solution of feed slurry.

“Fouling” refers to accumulation of materials on a membrane surface orstructure, which results in a decrease in flux.

“Flux” refers to a measurement of the volume of fluid that passesthrough a membrane during a certain time interval for a set area ofmembrane (i.e., gallons of permeate produced per ft² of membrane per day(gfd) or liters per m² per hour).

“Instantaneous flux” refers to flux measured at a given moment in time.

“Line-Out Study” refers to a procedure of measuring membrane flux overtime in order to determine eventual stability.

“Optimum differential pressure” refers to a differential pressure valueabove which the rate of change of flux with time, or the productivity ofthe filtration system, decreases.

“Percent recovery” refers to a ratio of permeate flow rate to feed flowrate.

“Permeate,” also known as “filtrate,” refers to the portion of slurrythat percolates through a membrane. The amount of solids and theparticle size of solids contained in the filtrate are determined by thepore size of the discriminating membrane, among other factors.

“Surfactant” or “surface acting agent” refers to any compound thatreduces surface tension when dissolved or suspended in water or watersolutions, or which reduces interfacial tension between two liquids, orbetween a liquid and a solid. In a related aspect, there are at leastthree categories of surface active agents: detergents, wetting agents,and emulsifiers; all use the same basic chemical mechanism and differ,for example, in the nature of the surfaces involved.

“Detergent” refers to an emulsifying agent or surface active agent madeusually by action of alkali on fat or fatty acids, such as, hut notlimited to, the sodium or potassium salts of such acids, or sulfonateswhich are formed when sulfonic acid is reacted with alkanes. In oneembodiment, detergent may include any of numerous syntheticwater-soluble or liquid organic preparations that are chemicallydifferent from soaps but are able to emulsify oils, hold dirt insuspension, and act as wetting agents.

“Heavy oil” refers to heavy and ultra-heavy crudes, including but notlimited to resids, coals, bitumen, tar sands, etc. Heavy oil feedstockmay be liquid, semi-solid, and/or solid. Examples of heavy oil feedstockthat might be upgraded as described herein include but are not limitedto Canada Tar sands, vacuum resid from Brazilian Santos and Camposbasins, Egyptian Gulf of Suez, Chad, Venezuelan Zulia, Malaysia, andIndonesia Sumatra. Other examples of heavy oil feedstock include bottomof the barrel and residuum left over from refinery processes, including“bottom of the barrel” and “residuum” (or “resid”)—atmospheric towerbottoms, which have a boiling point of at least 343° C. (650° F.), orvacuum tower bottoms, which have a boiling point of at least 524° C.(975° F.), or “resid pitch” and “vacuum residue”—which have a boilingpoint of 524° C. (975° F.) or greater. Properties of heavy oil feedstockmay include, but are not limited to: TAN of at least 0.1, at least 0.3,or at least 1; viscosity of at least 10 cSt; API gravity at most 20 inone embodiment, and at most 10 in another embodiment, and less than 5 inanother embodiment. A gram of heavy oil feedstock typically contains atleast 0.0001 grams of Ni/V/Fe; at least 0.005 grams of heteroatoms; atleast 0.01 grams of residue; at least 0.04 grams C5 asphaltenes; atleast 0.002 grams of MCR; per gram of crude; at least 0.00001 grams ofalkali metal salts of one or more organic acids; and at least 0.005grams of sulfur. In one embodiment, the heavy oil feedstock has a sulfurcontent of at least 5 wt. % and an API gravity of from −5 to +5. A heavyoil feed comprises Athabasca bitumen (Canada) typically has at least 50%by volume vacuum reside. A Boscan (Venezuela) heavy oil feed may containat least 64% by volume vacuum residue.

As used, herein, the term “spent catalyst” or “used catalyst” refers toa catalyst that has been used in a hydroprocessing operation and whoseactivity has thereby been diminished, remain unchanged or has beenenhanced. For example, if a reaction rate constant of a fresh catalystat a specific temperature is assumed to be 100%, the reaction rateconstant for a spent catalyst temperature is 80% or less in oneembodiment, and 50% or less in another embodiment. In one embodiment,the metal components of file spent catalyst comprise at least one ofGroup VB, VIB, and VIII metals, e.g., vanadium, molybdenum, tungsten,nickel, and cobalt. The most commonly encountered metal is molybdenum.In one embodiment, the metals in a spent catalyst are sulfides of Mo,Ni, and V.

The terms “treatment,” “treated,” “upgrade”, “upgrading” and “upgraded”,when used in conjunction with a heavy oil feedstock, describes a heavyoil feedstock that is or has been subjected to hydroprocessing, or aresulting material or crude product, having a reduction in the molecularweight of the heavy oil feedstock, a reduction in the boiling pointrange of the feedstock, a reduction in the concentration of asphaltenes,a reduction in the concentration of hydrocarbon free radicals, and/or areduction in the quantity of impurities, such as sulfur, nitrogen,oxygen, halides, and metals.

In one embodiment, the invention relates to an integrated facility (orsystem) comprising: 1) a heavy oil upgrade process (or zone), wherein aheavy oil feed is converted to lighter products; 2) a deoiling processor zone, wherein residual heavy oil and heavier product oils areseparated from the spent slurry catalyst for subsequent recovery; 3) ametal recovery zone, wherein metals are recovered from the spentcatalyst; and 4) a catalyst synthesis zone, wherein catalysts aresynthesized from metals from sources including metals recovered from thespent catalyst. Any of the zone can be operated in either batch mode,continuous mode, or combinations thereof.

In one embodiment of the invention with the recovery/separation of spentcatalyst from heavy oil, the heavy oil conversion rate can be up to100%. In one embodiment, an integrated system with a deoiling zone forrecovery/separation of spent catalyst allows for up at least 99% heavyoil conversion rate. In another embodiment, the overall heavy oilconversion rate is at least 99.5%. As used herein, conversion raterefers to the conversion of heavy oil feedstock to less than 1000° F.(538° C.) boiling point materials.

Heavy Oil Upgrading. The upgrade or treatment of heavy oil feeds isgenerally referred herein as “hydroprocessing.” Hydroprocessing is meantany process that is carried out in the presence of hydrogen, including,but not limited to, hydroconversion, hydrocracking, hydrogenation,hydrotreating, hydrodesulfurization, hydrodenitrogenation,hydrodemetallation, hydrodearomanzation, hydroisomerization,hydrodewaxing and hydrocracking including selective hydrocracking. Theproducts of hydroprocessing may show improved viscosities, viscosityindices, saturates content, low temperature properties, volatilities anddepolarization, etc.

Heavy oil upgrade is utilized to convert heavy oils or bitumens intocommercially valuable lighter products, e.g., lower boilinghydrocarbons, in one embodiment include liquefied petroleum gas (LPG),gasoline, jet, diesel, vacuum gas oil (VGO), and fuel oils.

In the heavy oil upgrade process, a heavy oil feed is treated orupgraded by contact with a slurry catalyst feed in the presence ofhydrogen and converted to lighter products, generating: a) an effluentstream containing a mixture of the upgraded products, the slurrycatalyst, the hydrogen containing gas, and unconverted heavy oilfeedstock, which effluent stream is subsequently passed on to aseparation zone; and b) a stream defined herein as unconverted slurrybleed oil stream (“USBO”), comprising spent finely divided unsupportedcatalyst, carbon fines, and metal fines in unconverted resid hydrocarbonoil and heavier hydrocracked liquid products (collectively, “heavy oil”)as slurry catalyst. The solids content in the USBO stream can be in therange of about 5-50 weight % in one embodiment. In a second embodiment,10-30 weight %. In a third embodiment, about 15-25 weight %. In a fourthembodiment, the solid catalyst concentration is as low as 2 wt. %. Inone embodiment, the upgrade process comprises a plurality of reactors orcontacting zones, with the reactors being the same or different inconfigurations. Examples of reactors that can be used herein includestacked bed reactors, fixed bed reactors, ebullating bed reactors,continuous stirred tank reactors, fluidized bed reactors, sprayreactors, liquid/liquid contactors, slurry reactors, slurry bubblecolumn reactors, liquid recirculation reactors, and combinationsthereof.

In one embodiment, at least one of the contacting zones furthercomprises an in-line hydrotreater, capable of removing over 70% of thesulfur, over 90% of nitrogen, and over 90% of the heteroatoms in thecrude product being processed. In one embodiment, the upgraded heavy oilfeed from the contacting zone is either fed directly into, or subjectedto one or more intermediate processes and then fed directly into theseparation zone, e.g., a flash drum or a high pressure separator,wherein gases and volatile liquids are separated from the non-volatilefraction, e.g., the unconverted slurry bleed oil stream (“USBO”).

In one embodiment, at least 90 wt % of heavy oil feed is converted tolighter products in the upgrade system. In a second embodiment, at least95% of heavy oil feed is converted to lighter products. In a thirdembodiment, the conversion rate is at least 98%. In a fourth embodiment,the conversion rate is at least 99.5%. In a fifth embodiment, theconversion rate is at least 80%.

In one embodiment, the heavy oil upgrade process employs a slurrycatalyst. The catalyst slurry can be concentrated prior to heavy oilupgrading, for example, to aid in the transport of catalyst (slurry) tothe heavy oil upgrading location. Effluent streams from the reactor,perhaps following downstream processing, such as, for example,separation(s), can include one or more valuable light products as wellas a stream containing spent slurry/unsupported catalyst in heavy oilcomprising unconverted feed.

Catalyst Synthesis: In one embodiment, the spent slurry catalyst to beseparated from heavy oil originates from a dispersed (bulk orunsupported) Group VIB metal sulfide catalyst promoted with at least oneof: a Group VB metal such as V, Nb; a Group VIII metal such as Ni, Co; aGroup metal such as Fe; a Group IVB metal such as Ti; a Group metal suchas Zn, and combinations thereof. Promoters are typically added to acatalyst formulation to improve selected properties of the catalyst orto modify the catalyst activity and/or selectivity. In anotherembodiment, the slurry catalyst originates from a dispersed (bulk orunsupported) Group VIB metal sulfide catalyst promoted with a Group VIIImetal for hydrocarbon oil hydroprocessing.

In one embodiment, the slurry catalyst originates from a multi-metalliccatalyst comprising at least a Group VIB metal and optionally, at leasta Group VIII metal (as a promoter), wherein the metals may be inelemental form or in the form of a compound of the metal. The metals foruse in making the catalyst can be metals recovered from a downstreammetal recovery unit, wherein metals such as molybdenum, nickel, etc.,are recovered from the deoiled spent slurry catalyst for use in thesynthesis of fresh/new slurry catalyst.

In one embodiment, the slurry catalyst originates from a catalystprepared from a mono-, di, or polynuclear molybdenum oxysulfidedithiocarbamate complex. In a second embodiment, the catalyst isprepared from a molybdenum oxysulfide dithiocarbamate complex. In oneembodiment, the slurry catalyst originates from a catalyst prepared fromcatalyst precursor compositions including organometallic complexes orcompounds, e.g., oil soluble compounds or complexes of transition metalsand organic acids. Examples of such compounds include naphthenates,pentanedionates, octoates, and acetates of Group VIB and Group VIImetals such as Mo, Co, W. etc. such as molybdenum naphthanate, vanadiumnaphthanate, vanadium octoate, molybdenum hexacarbonyl, and vanadiumhexacarbonyl.

In one embodiment, the catalyst slurry comprising catalyst particles (orparticles) having an average particle size of at least 1 micron in ahydrocarbon oil diluent. In another embodiment, the catalyst slurrycomprises catalyst particles having an average particle size in therange of 1-20 microns. In a third embodiment, the catalyst particleshave an average particle size in the range of 2-10 microns. In oneembodiment, the slurry catalyst comprises a catalyst having an averageparticle size ranging from nanometer size to about 1-2 microns. Inanother embodiment, the slurry catalyst comprises a catalyst havingmolecules and/or extremely small particles (i.e., less than 100 nm, lessthan about 10 nm, less than about 5 nm, and less than about 1 nm),forming particles or aggregates having an average size ranging from 1 to10 microns in one embodiment, 1 to 20 microns in another embodiment, andless than 10 microns in yet a third embodiment, in one embodiment, thecatalyst particles are colloidal in size.

Deoiling Zone. The system to extract/recover/separate heavy oil from theslurry catalyst and or concentrate a catalyst slurry is called adeoiling zone (or unit). In one embodiment of a deoiling zone, heavy oilis extracted or separated from catalyst particles, forming clean, driedsolids, thr subsequent recovery in the metal recovery zone. In oneembodiment, the deoiling zone comprises a number of separate sub-unitsincluding solvent wash (solvent extraction), filtration, drying, andsolvent recovery sub-units.

In one embodiment, the deoiling zone is used to concentrate a catalystslurry to a solids contents of, for example, about 60-70 weight %. Due,in part, to the concentrated catalyst slurry having a reduced volume ascompared to the volume of the catalyst slurry prior to concentration,the concentrated catalyst slurry can then be more easily transported toa heavy oil upgrading site or reactor, where it can be reconstituted toa solids contents of, for example, about 5 weight %, prior to heavy oilupgrading.

The term “spent catalyst slurry” refers to a catalyst slurry, whether aspent catalyst slurry to be separated from heavy oil, or a freshcatalyst slurry that needs to be concentrated.

The term “extract” may be used interchangeably with “separate” or“recover” (or grammatical variations thereof), denoting the separationof heavy oil from catalyst particles (or particles).

In one embodiment, the feed stream to the deoiling zone is a catalystbleed stream from a heavy oil upgrade or vacuum resid unit, e.g.,unconverted slurry bleed oil (“USBO”) stream, comprising spent finelydivided unsupported catalyst, carbon fines, and metal fines inunconverted resid hydrocarbon oil and heavier hydrocracked liquidproducts (collectively, “heavy oil”). In one embodiment, the USBO feedstream to the deoiling process has a spent catalyst concentration (assolids) ranging from 5-50 weight %. In another embodiment, the spentcatalyst solid ranges from 10 to 20 wt. % of the total USBO feed stream.In yet another embodiment, the solid catalyst concentration is as low as2 wt. %. The clean dried solids leaving the deoiling process consistsessentially of spent catalyst solids, in one embodiment having less than1 wt. % oil, on a solvent free basis, with less than 500 ppm of solvent.

In one embodiment, the feedstock stream is first combined with solventto form a combined slurry-solvent stream prior to being filtered viamembrane filtration. In another embodiment, the feedstock stream and thesolvent are fed to the filter as separate feed streams wherein they arecombined in the filtration process. In one embodiment, fresh solvent isused for the solvent wash. In another embodiment, recycled solvent fromanother part of the process is used. In yet a third embodiment, amixture of fresh solvent and recycled solvent is employed. In a fourthembodiment, fresh solvent and recycled solvent are employed as separatestreams. The feedstock and solvent streams can be combined prior to thedeoiling zone or in the deoiling zone.

Via membrane filtration, spent catalyst is separated from the heavy oil,i.e., “deoiled,” in solvent as a separate stream. A second stream isproduced comprising the heavy oil and solvent. Solvent can besubsequently separated from the catalyst using processes includingevaporation to dryness. Solvent can also be recovered from the streamcomprising the heavy oil and solvent for subsequent reuse, with therecovered heavy oil being a product.

In one embodiment, in addition to or in place of membrane filtration,other separation techniques can be employed including inclined platesettlers, conventional settling tanks, inclined settlers with vibratoryseparation device, as long as the vibration is not transmitted to thesettler/sedimentation unit.

Membrane Filtration: In one embodiment, a membrane filtration assembly,e.g., microfiltration, is employed in the deoiling zone to separate theheavy oil from the catalyst. In the filtration assembly, a feed streamcomprising slurry catalyst in heavy oil is transformed into two streams,a first stream containing primarily hydrocarbons, e.g., a mixture ofheavy oil and solvent, and a second stream containing catalyst solidswith reduced heavy oil concentration in solvent. As used in the contextof the deoiling zone/membrane filtration, “heavy oil” will refer tounconverted resid hydrocarbon oil, heavier hydrocracked liquid products,and mixtures thereof.

The membranes employed can be of the “tortuous-pore” or “capillary-pore”type, or a combination of multiple membrane layers, some tortuous-poremembranes some capillary-pore membranes. As used herein, tortuous-porerefers to membranes having a structure resembles a sponge with a networkof interconnecting tortuous pores. Capillary-pore refers to membraneshaving approximately straight-through cylindrical capillaries.

Any suitable filtration medium (membrane) can be utilized in thefiltration assembly. In one embodiment, the filtration medium is aporous material which permits heavy oil below a certain size to flowthrough as the filtrate (or permeate) while retaining the spent catalystparticles in the retentate. In one embodiment, the filter medium is ofsufficient pore size for removing at least 50% of the heavy oil from thespent catalyst, i.e., for at least 50% of the heavy oil to pass throughthe filter membrane. In another embodiment, the filter membrane is ofsufficient pore size for at least 60% of the heavy oil to pass throughthe membrane. In a third embodiment, the membrane is of sufficient poresize for at least 70% of the heavy oil to pass through the membrane. Ina fourth embodiment, it is of sufficient size for at least 75% of theheavy oil to pass through the membrane.

In one embodiment, the filtration medium is a filtration membrane havingan effective pore rating (“average pore size”) of about 5 microns orless is used for example, about 0.1-0.3 μm, about 0.05-0.15 μm, or about0.1 μm. In a third embodiment, an effective pore rating of about 1micron or less. In a fourth embodiment, about 0.5 micron or less. In yeta fifth embodiment, the membrane has an effective pore rating of atleast 0.01 micron. In a sixth embodiment, from 0.1 to 1 micron. In aseventh embodiment, an effective pore rating of at least 1 micron. In aneight embodiment, an effective pore rating of less than 10 microns.

Polymers, organic materials, inorganic ceramic materials, and metals aresuitable for use as construction materials for the membrane, as long asthey are solvent stable. The term “solvent-stable” refers to a materialthat does not undergo significant chemical changes to substantiallyimpair the desired properties of the material. Stability can be verifiedby various well-known techniques, which include, but are not limited to,soaking test, scanning electron microscopy (SEM), X-ray diffraction(XRD), differential scanning calorimetry (DSC) and thermogravimetricanalysis (TGA).

In one embodiment, the filtration membrane is made ofpolytetrafluoroethylene (Teflon®), for example, polytetrafluoroethyleneon woven fiberglass, which can withstand temperatures of 130° C. (266°F.). With the use of polytetrafluoroethylene, the membrane is chemicallyinert, can handle continuous pH levels of 0-14.

In one embodiment, the filtration membrane comprises a polymericmaterial selected from the group of poly(acrylic acids),poly(acrylates), polyacetylenes, poly(vinyl acetates),polyacrylonitriles, polyamines, polyamides, polysulfonamides,polyethers, polyurethanes, polyimides, polyvinyl alcohols, polyesters,cellulose, cellulose esters, cellulose ethers, chitosan, chitin,elastomeric polymers, halogenated polymers, fluoroelastomers, polyvinylhalides, polyphosphazenes, polybenzimidazoles,poly(trimethylsitylpropyne), polysiloxanes, poly(dimethyl siloxanes),and copolymers blends thereof. These polymers can be physically orchemically cross-linked to further improve their solvent stability.

In one embodiment, the membrane comprises an inorganic material such asceramics (silicumcarbide, zironiumoxide, titaniumoxide, etc.) having theability to withstand high temperatures and harsh environments. In oneembodiment, the membrane is constructed from a woven fabric coated witha nanomaterial, e.g., an inorganic metal oxide, allowing the membrane tobe in the form of a flexible ceramic membrane foil with advantages ofboth ceramic and polymeric membranes. In another embodiment, thefiltration membrane is constructed from a metal such as stainless steel,titanium, bronze, aluminum or nickel-copper alloy. In yet anotherembodiment, the membrane is constructed from materials such as sinteredstainless steel with an inorganic metal oxide coating, e.g., a titaniumoxide coating.

In one embodiment, the deoiling zone comprises a membrane that israpidly displaced in a horizontal direction. A retentate of the membranecomprises the fine catalyst and a permeate of the membrane comprises theheavy oil. In particular, rapidly displacing the membrane in ahorizontal direction can comprise rotating the membrane.

In one embodiment, filtration membrane operating pressure is in therange of about 30-100 psi (about 2-7 bar). Filtering can be conducted ata temperature of about 50-200° C. and a pressure of about 80-200 psi,for example at a temperature of about 100° C. and a pressure of about 90psi. In one embodiment, the deoiling zone comprising multiple filtrationunits is operated at a pressure in the range of about 20-400 psi, forexample, about 30-300 psi or about 50-200 psi. Pressure drops across themembrane in the filtration units, referred to as the transmembranepressure, are in the range of about 0-100 psi, for example, about 0-50psi or about 0-25 psi. In one embodiment, the temperature of thedeoiling zone is in the range of about 100-500° F., for example, about150-450° F. or about 200-400° F.

Solvent Extraction/Addition: In the deoiling zone, an extracting mediumis employed for the extraction/separation of the heavy oil from thespent catalyst. Solvent addition to an oil/catalyst slurry or an oilrich sob/era/oil/catalyst slurry is also used herein to reduce theeffective viscosity and density of the continuous liquid phasecontaining the suspended catalyst particles, thereby enhancing thesettling of the particles and subsequent separation of the slurry intotwo phases. In one embodiment, the extraction medium is a compositioncomprising a light specific gravity solvent or solvent mixtures, suchas, for example, xylene, benzene, toluene, kerosene, reformate (lightaromatics), light naphtha, heavy naphtha, light cycle oil (LCO), mediumcycle oil (MCO), propane, diesel boiling range material, which is usedto “wash” the feed stream to the deoiling zone. In one embodiment, thesolvent is a commercially available solvent such as ShelSol™ 100 seriessolvent.

In one embodiment, the washing/mixing with solvent (i.e., solventextraction) is done prior to membrane filtration, e.g., in a separatetank such as a settling tank/mixing tank prior to the membranefiltration unit. In another embodiment, the washing/mixing with solventis in-situ in a membrane filtration unit. In one embodiment, alightspecific gravity solvent and feed stream comprising spent slurrycatalyst are supplied in separate stream to one or more filtration unitsin a counter-current fashion. In yet another embodiment, thewashing/mixing with solvent is in a concurrent fashion.

In one embodiment, the solvent can be a recycled solvent (used solvent)recovered from a process step within the deoiling zone. In anotherembodiment a solvent mixture containing at least any two of all theaforementioned solvents is used.

In one embodiment, the feedstock stream containing slurry catalyst,i.e., catalyst particles in heavy oil, is mixed/washed with solvent in avolume ratio of ranging from 0.10/1 to 100/1 (based on the spentcatalyst slurry volume). In a second embodiment, the solvent is added ina volume ratio of 0.50/1 to 50/1. In a third embodiment, at a volumeratio of 1/1 to 25/1.

In one embodiment, the feedstock stream containing slurry catalyst, ismixed/washed with a sufficient amount of solvent to reduce the heavy oilconcentration in the feedstock stream by at least 40%. In a secondembodiment, a sufficient amount of solvent is added to reduce the heavyoil concentration by at least 50%. In a third embodiment, the heavy oilconcentration is reduced by at least 60%.

In one embodiment with 50 to 90 wt % heavy oil in the feedstock streamcomprising catalyst particles and heavy oil and wherein the heavy oil isessentially in a colloidal suspension, a sufficient amount of solvent isadded to break up the colloidal suspension of the heavy oil and reducethe effective viscosity and density of the continuous liquid phase (thatis, the oil/solvent mixture), thereby causing the catalyst particlessuspended in the oil/solvent mixture to separate into two phases faster.In one embodiment, the sufficient amount of solvent added ranges from0.50/1 to 50/1 (volume ratio of solvent to mixture of catalyst particlesin heavy oil). In a second embodiment, at a volume ratio of 1/1 to 25/1.

In one embodiment with 50 to 90 wt % heavy oil in the feedstock streamcomprising catalyst particles and heavy oil and wherein it takes afairly substantial amount of time for the particulates, i.e., the slurrycatalyst in slurry oil, to settle, a sufficient amount of solvent isadded to increase the settling/sedimentation rate of the particulates byat least 25%. In another embodiment, by at least two folds. In yetanother embodiment, by at least a factor of 1.25. In one embodiment, theaddition of the solvent will cut down the amount of time for theparticulates to settle by half. In another embodiment, the added solventincreases the sedimentation rate at least three folds.

In one embodiment, in addition to or instead of the solvent addition,the feedstock stream containing catalyst particles in heavy oil (andoptionally with solvent) is heated to a sufficiently high temperature todecrease the density and viscosity of the catalyst/heavy oil mixture,thereby enhancing the settling of the particulates. In one embodiment,the mixture is heated to a temperature of up to the saturationtemperature of the solvent at the corresponding operating pressure. Inone embodiment, the maximum operating pressure is 500 psig.

The addition of solvent to an oil/catalyst feed slurry (or an oil richsolvent/oil/catalyst slurry) reduces the effective viscosity and densityof the continuous liquid phase containing the suspended catalystparticles, thereby enhancing the settling of the particles andsubsequent separation of the slurry into two phases: a bottom phasecomprising catalyst particles, solvent, and a heavy oil concentrationthat is less than the initial heavy oil concentration in the feedstream; and the top phase comprising heavy oil in solvent and virtuallysolids free. The two phases can be subsequently gravity separated withthe use of a settling tank.

It is noted that catalyst particles settle significantly faster to thebottom (i.e., as in a two phase mixture) with the reduction of the heavyoil concentration. Thus in one embodiment, the washing/mixing withsolvent is carried out with the use of at least one separator such as asettling tank to allow for the settling of the catalyst particles at thebottom, and successive removal of the lighter phase comprising solventand portions of the heavy oil from the separator until most of heavy oilis removed from the catalyst particles, leaving a stream consistingmostly of catalyst solids in light specific gravity solvent. The use ofsolvent in combination of a separator to remove some of the heavy oilfrom the catalyst particles is herein after referred to as “solventseparation.”

In one embodiment, the washing/mixing and subsequent phase separationsteps take place in a settling tank. In another embodiment, thewashing/mixing/phase separation steps are repeated at least once insettling tank(s). In a third embodiment, settling tank(s) are used incombination with filtration units, cross-flow filtration, cross-flowsedimentation, etc. for most of the heavy oil to be phase-separated fromcatalyst particles first using settling tanks, then for the residualheavy oil to be separated with filtration technology. In a fourthembodiment, filtration technology is used for initial solvent additionand oil removal, and settling tank(s) is used for the removal of theresidual oil from the solvent-rich catalyst slurry. Yet in anotherembodiment, the separation is effected by at least one unit of combinedsettler/filter assembly.

In one embodiment, instead of or in addition to the use of settlingtanks for the separation of the fiat and heavy phases, other separationmeans known in the art can be employed, including but not limited tocentrifugal force enhanced settling devices such as centrifuges,filtering centrifuges, and cyclonic separators. In another embodiment,an inclined plate settler such as Lamella® Gravity Settler is used, inyet another embodiment, the separation is enhanced with the use ofelectrical coulomb forces, electrical currents, and/or magnetic forcesas a magnetic field, or a series of magnetic fields. It should be notedthat enhanced separation means can be used with the settling tanks,centrifugal force enhanced settling devices as well as with the membranefiltration system, e.g., dialfiltration, cross-flow filtration, dynamicfiltration, etc.

In one embodiment, the mixture of catalyst particles in heavy oilemulsion and/or solvent is subject to an electric field to enhance theeffectiveness of the separation. In yet another embodiment, the mixtureof catalyst particles in solvent and/or heavy oil emulsion is exposed toa magnetic field to enhance the migration of the catalyst particles awayfrom the heavy oil, providing a phase with reduced heavy oilconcentration.

In one embodiment, the additional solvent is rendered magnetic by mixinga particulate magnetic material therewith prior to or concurrent withthe addition of the feedstock stream containing slurry catalyst. As usedherein, the term “magnetic material” means a material havingferromagnetic or strong paramagnetic properties. Suitable magneticmaterials include magnetite, ferrites, hematite, magnetite, pyrrhotiteand metals, alloys and compounds containing iron, nickel or cobalt. Inone embodiment, the magnetic material is magnetite. The magneticmaterial may be derived from various sources. In one embodiment, themagnetic materials are first rendered hydrophobic prior to mixing withthe solvent by coating the surfaces with a polar surfactant whichadsorbs onto the particle surfaces, e.g., compounds with functionalgroups having anionic, cationic or amphoteric properties. While in aseparator like a settling tank, the mixture comprising the solvent,catalyst particles and heavy oil is subjected to a magnetic field whichaccelerates phase separation because of the magnetic nature imparted bythe magnetic organic solvent.

The number of separators such as settling tanks and the order of theseparators relative to the filtration assembly can be arranged tooptimize the separation of the heavy oil from the catalyst particulates.With solvent separation, an initial heavy oil concentration of up to 90wt. % in a feed stream comprising a catalyst slurry to less than 50 wt.% in one embodiment, less than 30 wt. % in a second embodiment, lessthan 10 wt. % in a third embodiment, less than 5 wt. % in a fourthembodiment, and less than 2 wt. % in a fourth embodiment. Thecomposition with reduced heavy oil concentration can be routed to afiltration assembly for further separation.

It should be noted that the operation of any of the solvent separationmeans and or filtering units, e.g., settling tanks, centrifugal forceenhanced settling devices, inclined settlers, dialfiltration units,cross-flow filtration units, dynamic filtration units, filtrationsedimentation units, can be in any of a batch mode, a continuous mode,semi-batch mode, semi-continuous mode, or combinations thereof.Furthermore, the addition of the solvent to the feed stream or any ofthe filtration unit can be carried out intermittently, progressively,abruptly, sequentially, or combinations thereof.

In one embodiment after a sufficient amount of solvent is added toreduce the heavy oil concentration of at least 50%, the streamcomprising solvent, catalyst particles and heavy oil is put into asettling tank to allow separation by gravity. In one embodiment aftersuccessive separation steps with a plurality of settling tanks, at least90% of the heavy oil is removed from the catalyst particles.

In one embodiment, the mixing of solvent and feedstock is for asufficient amount of time and at a temperature sufficient to preventsubstantial asphaltenes precipitation prior to and during filtration. Inone embodiment, this temperature ranges from about 50 to 150° C. In oneembodiment, the mixing is in the range from 15 minutes to an hour. Inanother embodiment, for at least 20 minutes. In another embodiment in acontinuous process, the mixing of solvent and feedstock is less than 10minutes. In yet another embodiment with the mixing of solvent andfeedstock being in-situ in a filtering device, the mixing occurs in 5minutes or less.

Besides combining/washing the feedstock containing slurry catalyst inheavy oil with solvent prior to filtering, the retentate of the membranefrom the filtering process can also be washed with a solvent. Afterwashing in a filtration unit, a permeate (filtrate) stream comprisingheavy oil and solvent, can be recovered in addition to a retentatestream, comprising unsupported fine catalyst and solvent. Theunsupported fine catalyst can be subsequently separated from theretentate stream of the membrane.

In one embodiment, the solvent of the combined retentate-solvent streamis a different solvent than the solvent of the combined slurry-solventstream. In another embodiment, the solvent for use in the combinedretentate-solvent can be the same solvent as the solvent of the combinedfeedstock-solvent stream. In yet another embodiment, the solvent caninclude solvent from a different source than the solvent of the combinedfeedstock solvent stream. In another embodiment, solvent-rich permeatefrom at least one of the filter units can be the source of at least aportion of the solvent for the combined slurry-solvent stream and/or thecombined retentate-solvent stream.

In one embodiment, the retentate stream from a first filtration unit canbe combined with solvent prior to a next filtration unit in series,through which the combined retentate-solvent stream is filtered, in oneembodiment, a permeate (filtrate) stream of a later-staged filtrationunit (in a system with a plurality of filtration stages or units) can berecycled to be used as the solvent for use with the feed stream enteringan earlier staged filtration unit, forming a combined feedstock-solventstream.

In one embodiment, the retentate stream is further diluted with asolvent rich stream and passed to a succeeding filtration unit. In oneembodiment, the solvent rich stream is a stream of unconverted oil alongwith a solvent such as toluene, which is passed through the membrane ofa succeeding filtration unit. As the retentate streams move forward tosucceeding filtration units, the retentate streams can be sequentiallywashed counter-currently with toluene rich streams passed through themembranes of succeeding filtration units.

In one embodiment, the retentate streams are sequentially washed in a“counter-current” fashion, in that retentate streams pass from onefiltration unit to the next (e.g., five to six total stages), while thesolvent that is added to the retentate streams comes from one moredownstream filtration units. For example, in an embodiment, the solventcascades from the last filtration unit to the first filtration unit,counter to the flow of the retentate streams passing through thefiltration units. In this way, the liquid portion of the feed to thefirst filtration unit comprises no mixture of solvent and unconvertedoil, while the liquid portion of the feed to the last filtration unitcomprises substantially pure solvent, and the retentate stream of thelast filtration unit comprises the catalyst particles in substantiallypure solvent.

As illustrated in FIGS. 1A-1F, the filtration membranes employed can befabricated into various forms including a pressure leaf unit (eitherhorizontal or vertical type), a plate and frame unit (FIG. 1A), pleatedmembrane (FIG. 1B), a tubular/hollow module (1C), a plurality oftubular/hollow modules (FIG. 1D), a spiral wound form (1E), orcombinations thereof, e.g., a plurality of tubular modules with eachbeing of spiral wound form (not shown).

FIG. 1A is a cross-section view of a plate and frame (flat plate) unit.In one embodiment, the plate and frame (flat plate) unit can take sheetstock filtration membranes.

In FIG. 1B, a pleated filtration membrane is interposed between twopermeable sheets and is wound on a core having a plurality of collectionports. An outer guard is provided to protect the filtration membrane.The system is sealed by end plates at opposite ends of the filer. Heavyoil is collected from the collection ports and comes out of the outlet.In one embodiment of the pleated membrane of FIG. 1B, a sleeve is placedaround the cartridge and the housing so as to withdraw the retentatestream from the bottom of the housing, the cross-flow stream beingthereby forced into the pleats where it moves tangential to themembrane.

FIG. 1C illustrates a substantially tubular membrane filter having anouter housing, an inlet (feed), a retentate outlet and a permeate outlet(filtrate). Extending within the housing is at least a tubular filterwhich is parallel to the axis of the housing.

FIG. 1D is a second embodiment a tubular filter system with a pluralityof filter sleeves (hollow membrane tubes) running parallel to oneanother and to the axis of the housing.

FIG. 1E illustrates a spiral wound membrane module with alternatinglayers of membrane and separator screen being wound around a hollowcentral core. In operation, the feed stream is pumped into one end ofthe cartridge. The filtrate passes through the membrane and spirals tothe core of module, where it is collected for removal.

In one embodiment, the filtration assembly in the deoiling zonecomprises a plurality of filtration units thr effective removal of heavyoil from catalyst particles. In one embodiment, a filtration assemblywith a plurality of filtration units is capable of removing most of theheavy oil from catalyst particles, for a filtrate stream comprisingsolvent and at least 50% of the incoming heavy oil (in the feed streamof heavy oil and slurry catalyst), in another embodiment, a filtrationassembly with a plurality of filtration units is capable for removing atleast 90% of the heavy oil from the catalyst particles. In a thirdembodiment, at least 95% of the heavy oil is removed from the catalystparticles. In a fourth embodiment, a filtration assembly with aplurality of filtration units is capable for removing at least 99% ofthe heavy oil from the catalyst particles.

In one embodiment, the filtration assembly comprises between two to tenfiltration units. In another embodiment, at least four to eightfiltration units. In a third embodiment, the assembly comprises sixfiltration units. The filtration units employed in the deoiling zone canbe in any of the form of diafiltration, cross-flow filtration, dynamicfiltration, cross-flow sedimentation, co-current sedimentationseparation, countercurrent sedimentation separation, and combinationsthereof, which processes are to be described in further detail below.

In one embodiment of the membrane filtration process, each filtrationunit may comprise a plurality of stages, e.g., at least two stages ofcross-flow filtration, at least two stages of dialfiltration, orcombinations of cross-flow filtration, cross-flow sedimentation,co-current sedimentation separation, countercurrent sedimentationseparation, and/or dialfiltration and/or dynamic filtration, each beinga separate stage. The number of stages of filtration and the solvent toheavy oil ratio are set to achieve the required deoiling efficiency.

Diafiltration. In one embodiment, the membrane filtration is in the formof diafiltration. In the prior art, diafiltration is typically used forpurifying retained large molecular weight species, increasing therecovery of low molecular weight species, buffer exchange and simplychanging the properties of a given solution. With the fractionationprocess of diafiltration and with the use of solvent, heavy oilmolecules are washed through the membrane as filtrate, leaving thecatalyst solids (particles) in the retentate.

In one embodiment, diafiltration is in the form of a single stage. Inanother embodiment, the diafiltration unit comprises a plurality ofstages, e.g., at least several stages in one embodiment, between about 2and 5 stages in a second embodiment, and at least 7 in a thirdembodiment. With the use of diafiltration, the fine solid in the slurrycatalyst in a first solution (e.g., a heavy bleed oil or hydrocarbonsolution) is transferred to in a second solution (retentate) along witha solvent such as, for example, toluene or light naphtha. Heavy bleedoil is recovered in the filtrate stream along with solvent.

Dynamic Filtration. In one embodiment, one or more filtration unitsdescribed above may be replaced by one or more dynamic filtration units.

Dynamic filtration has been typically employed in treating wastewatercontaining particulate matters and waste oils. A dynamic filtrationassembly has the ability to handle a wide range of materials, to achievean appreciably high concentration of retained solids, to be operatedcontinuously over extended periods without the need for filter aidsand/or backflushing, and to achieve uniformly high filter performance tominimize the overall system size. The dynamic filtration assembly may beof any suitable configuration and will typically include a housing whichcontains a filter unit comprising one or more filtration media and ameans to effect relative movement between the filtration medium and thematerials to be filtered. The filtration media of the filter unit andthe means to effect relative movement between the fluid being filteredand the filtration medium may have any of a variety of suitableconfigurations. A variety of suitable motive means can be utilized tocarry out such relative motion, such as, for example, rotational,oscillation, reciprocating, or vibratory means.

Variable vibration amplitude and corresponding shear rate, oscillationfrequency, and shear intensity directly affect filtration rates.Shearing is produced by the torsion oscillation of the membrane. In oneembodiment of a dynamic filtration unit, the membrane oscillates with anamplitude of about 1.9-3.2 cm peak to peak displacement at the edge ofthe membrane. Optimal filtration rates can be achieved at high shearrates, and, since the concentrate is not degraded by shear, maximumshear is preferred, within practical equipment limitations. In oneembodiment, a dynamic filtration unit creates shear forces of at leastabout 20,000 sec⁻¹. In a second embodiment, at least about 100,000sec⁻¹. In another embodiment, the oscillation frequency is about 50-60Hz, for example, about 53 Hz, and produces a shear intensity of, forexample, about 150,000 sec⁻¹. In yet another embodiment, a shear forcebetween 20,000 and 100,000 sec⁻¹.

In one embodiment, the dynamic filtration assembly operates withrelatively low cross-flow velocities, thus preventing a significantpressure drop from the inlet (high pressure) to the outlet (lowerpressure) end of the device, which can lead to premature fouling of themembrane that creeps up the device until permeate rates drop tounacceptably low levels.

In one embodiment, operating pressure in a dynamic filtration assemblyis created by the feed pump. While higher pressures often produceincreased permeate flow rates, higher pressures also use more energy.Therefore, the operating pressure optimizes the balance between flowrates and energy consumption.

The dynamic filtration assembly may be of any suitable device. Suitablecylindrical dynamic filtration systems are described in U.S. Pat. Nos.3,797,662, 4,066,554, 4,093,552, 4,427,552, 4,900,440, and 4,956,102.Suitable rotating disc dynamic filtration systems are described in U.S.Pat. Nos. 3,997,447 and 5,037,562, as well as in U.S. patent applicationSer. No. 07/812,123. Suitable oscillating, reciprocating, or vibratorydynamic filtration assemblies are generally described in U.S. Pat. Nos.4,872,988, 4,952,317, and 5,014,564. Other dynamic filtration devicesare discussed in Murkes, “Fundamentals of Crossflow Filtration,”Separation and Purification Methods, 19(1), 1-29 (1990). In addition,many dynamic filtration assemblies are commercially available. Forexample, suitable dynamic filtration assemblies include Pall BDF-LAB,ASEA Brown Bovery rotary CROT filter, and New Logic V-SEP.

In one embodiment, the dynamic filtration unit employed is exemplifiedby a Vibratory Shear Enhanced Processing (V*SEP) system from New Logic.In a V*SEP system, a membrane module is used for separation, and whereinintense shear waves are imposed on the face of the membrane. V*SEPsystems have been typically employed in treating wastewater containingparticulate matters and waste oils. In one embodiment of the invention,V*SEP is used in the deoiling process.

In one embodiment, the use of dynamic filtration allows for the sameseparation efficiency to be achieved with fewer filtration stages. Inparticular, while typical cross-flow filters are usually limited tosolids contents of 25-35 weight % to avoid fouling of the membrane,dynamic filtration machines can accept higher solids contents (50-70weight %) while maintaining performance. Accordingly, the use of dynamicfiltration allows for greater oil removal per stage in diafiltrationmode, which would reduce the required number of stages.

In a dynamic filtration unit, a slurry to be filtered remains nearlystationary, moving in a leisurely, meandering flow. Shear cleaningaction is created by rapidly (i.e., 50-60 Hz) horizontally displacingthe membrane (i.e., in directions in the same plane as the face of themembrane). In an embodiment, the displacement is rotational oroscillatory. The shear waves produced by the displacement, or vibration,of the membrane cause solids and foulants to be lifted off the membranesurface and remixed with the slurry and expose the membrane pores formaximum throughput.

In an embodiment, dynamic filtration is used to aid in the transport ofcatalyst (slurry) prior to heavy oil upgrading. In yet anotherembodiment, dynamic filtration is used to concentrate catalyst slurry toa solids contents of, for example, about 60-70 weight %. Due, in part,to the concentrated catalyst slurry having a reduced volume as comparedto the volume of the catalyst slurry prior to concentration via dynamicfiltration, the concentrated catalyst slurry can then be more easilytransported to a heavy oil upgrading site or reactor, where it would bereconstituted to a solids contents of, for example, about 5 weight % inone embodiment, prior to heavy oil upgrading. In another embodiment, 2wt. %. In one embodiment, a catalyst slurry is concentrated with theremoval of at least 25% of the heavy oil. In another embodiment, acatalyst slurry is concentrated with a heavy oil removal of at least50%. In a third embodiment, at least 75% of the heavy oil is removed.

Sedimentation Separation. In one embodiment, the membrane filtration isin the form of a sedimentation separator. In sedimentation separation,the membrane is in the form of a plurality of channels arranged inparallel, and wherein the channels are inclined downward to facilitatesedimentation. In one embodiment, the channels are in the form of apleated membrane, e.g., a V-shape, a U-shape, etc. In anotherembodiment, the channels are in the form of tubes having elliptical,square, rectangular, or circular cross-sectional area. The term“channel” may be used interchangeably with “tube,” In one embodiment,the sedimentation separator further comprises a receiving chamber (asedimentation container) for receiving the retentate.

In one embodiment, the filter system has tube diameters or channelheights of 100 mm or less, a length of approx. 0.2 to 2.5 m and an angleof inclination at least 45° from a horizontal surface. In a secondembodiment, the angle of inclination ranges from 45 to 75°. In yetanother embodiment, the tubes (or channels) have a length in the rangefrom 0.2 to 1.5 m. In a fourth embodiment, the filter system has anangle of inclination from a horizontal surface in the range of 30 to60°.

The tubes can be of any shape or form. In one embodiment, the membranefilter is in the form of a plurality of channels having a rectangularcross section. In yet another embodiment, the membrane filter is in theform of a plurality of round tubes (circular cross-section area). In oneembodiment, the tubes (or channels) have uniform cross-section areas. Inanother embodiment, the cross-sectional areas vary depending on thelocation of the tubes.

In one embodiment of a membrane sedimentation system, the apparatuscomprises a module comprising the tubes (or channels), a covering plateand a return vessel (located beneath the inclined channels) for thecollection of the filtrate. In one embodiment, the apparatus furthercomprises inflow and outflow chamber plates to improve the flowdistribution. The plates can be either flat plates or shaped. In oneembodiment, the plates are arranged in close proximity and perpendicularto the inflow and outflow channels.

The membrane sedimentation separator for use in the deoiling zone can bein any of the form: counter-current sedimentation separator (asillustrated in FIG. 2), cross-flow sedimentation separator (asillustrated in FIG. 3), and co-current sedimentation separator (notshown). As shown in FIG. 2 of an embodiment of counter-currentsedimentation separation, the solvent stream and feed stream comprisingslurry catalyst in heavy oil are provided to the receiving chamber astwo separate opposite (counter-current) flows. FIG. 3 illustrates anembodiment of a cross-flow sedimentation separator, with the inletcomprising solvent, slurry catalyst in heavy oil entering one side ofchannels and an outflow for the filtrate (comprising heavy oil andsolvent) on the opposite side of the channel. A pyramidal receivingchamber is located beneath the channels for the collection of theretentate (comprising slurry catalyst and solvent).

In one embodiment, the membrane filtration system comprises a pluralityof different or the same sedimentation separators, two cross-flowsedimentation separators in series, a dynamic filtration system inseries with a counter-current sedimentation separator, or a combinationof cross flow sedimentation, co-current sedimentation, conventionalsettling tank, inclined settler with a dynamic filtration system (avibratory separation device), as long as the vibration from the dynamicfiltration unit is not transmitted to the settler/sedimentation unit.

In one embodiment, a feed stream to the membrane filtration unitcontaining 60-95 wt. % heavy oil and 2-40 wt. % spent catalyst (assolids, in the form of slurry catalyst) may exit the filtration unit asa retentate stream containing 2-40 wt. % catalyst (as solids), 0.01 to 1wt. % heavy oil, and with the remainder as solvent. In a secondembodiment, the retentate stream exiting membrane filtration may containanywhere from 0.05 to 0.5 wt. % heavy oil, on a solvent-free basis. In athird embodiment, the amount of heavy oil remaining in the retentateranges from 0.1 to 0.3 wt. %.

In the deoiling zone, the slurry catalyst in heavy oil is solvent washedand separated in mixed stream is solvent washed in a deoiling zone andtransferred from a heavy, USBO into a low boiling range solvent. Theproducts from the deoiling zone include a stream with the catalyst and ahigher percentage of solvent and a stream without catalyst and with arelatively high percentage of USBO. From the deoiling zone a streamconsisting of solvent and carrier oil mixture is routed to a splittercolumn, which produces an overhead stream of solvent, which isrecirculated to solvent tankage for use in the washing process, and abottoms stream of carrier oil, which is sent to product recovery, ahydroprocessing section, or to another residue disposition unit.

In one embodiment after membrane filtration (e.g., filtration using anyof cross-flow filtration, diafiltration, dynamic filtration, etc.), thefiltrate product comprising solvent and heavy oil mixture is routed to aseparator e.g., a splitter column, for the separation and subsequentrecovery of solvent and heavy oil. Solvent (and any residual heavy oil)can be subsequently separated from the catalyst particles in theretentate stream using various separation means including drying,detergent washing, ultrasonic cleaning, plasma cleaning, and the like.In one embodiment, the retentate stream comprising mostly slurrycatalyst in solvent can be sent to a drying zone.

In one embodiment, the splitter column produces an overhead stream ofsolvent which can be rerouted to a solvent tank for re-use in thesolvent washing process, and a bottoms stream of carrier oil(unconverted heavy oil and heavier hydrocracked liquid products) whichcan be sent to product recovery, a hydroprocessing unit, or a residuedisposition unit.

Drying Zone: The retentate (bottoms) stream consisting of highlyconcentrated spent catalyst in solvent in one embodiment is sent to adrying zone for final devolatilization. Deoiling followed by dryingallows for production of a sufficiently hydrocarbon-dry material to meetdownstream metals recovery requirements.

In one embodiment, the feed stream to the drying zone comprises between50 to 90 wt. % hydrocarbons, and the remainder being catalyst particles.Most of the hydrocarbons are in the form of solvent, and with residualheavy oil making up less than 5 wt. % of the total stream in oneembodiment, less than 3 wt. % in another embodiment, and less than 0.1wt. % in yet another embodiment.

In one embodiment, the drying step can involve, for example, evaporationat ambient conditions, warming in a dryer, or processing through arobust thin-film (or wiped-film) combination type dryer or evaporator.In another embodiment, the drying step utilizes an apparatus that wouldconvert the catalyst to a free-flowing granular state with a minimumtime of exposure to heat and vacuum, e.g., a nitrogen charged furnace.In one embodiment, the drying apparatus is selected from an indirectfired kiln, an indirect fired rotary kiln, an indirect fired dryer, anindirect fired rotary dryer, an electrically heated kiln, anelectrically heated rotary kiln, a microwave heated kiln, a microwaveheated rotary kiln, a vacuum dryer, a thin film dryer, a flexicoker, afluid bed dryer, a shaft kiln dryer or any such drying device. Retentatestream from the filtration unit can be fed to the drying apparatuseither co-currently or counter-currently with the gas feed, which can beoxidative, reducing, or inert gas.

In one embodiment, the drying apparatus is a thin film dryer, athin-film evaporator, a wiped film dryer, or a wiped-film evaporator,which is efficient in rapidly exposing the surfaces of the catalystparticles to the heat transfer medium. In one embodiment, the dryingapparatus is a vertical thin-film dryer, a vertical thin-filmevaporator, a vertical wiped-film dryer, or a vertical wiped-filmevaporator. In another embodiment, the apparatus is a horizontal thinfilm dryer, a horizontal thin-film evaporator, a horizontal wiped-filmdryer, or a horizontal wiped-film evaporator. In a third embodiment, theapparatus is a Combi dryer combining vertical and horizontal designs)from LCI Corporation. The thin film or wiped-film dryer/evaporator canbe operated in batch or continuous modes with a wide range of residencetimes depending on the configuration of the dryer.

In one embodiment, the drying apparatus is a rotary kiln dryer, whichcan be either a rotating inclined cylinder or a rotating heat exchanger.In one embodiment, the rotary kiln is one of a direct fired rotary kiln,an indirect fired rotary dryer, an electrically heated rotary kiln, anda microwave heated rotary kiln. Residence time in the rotary kiln dryerdepends on the dimension of the kiln, and varies from 2 to 250 minutes.

In one embodiment, the drying treatment of spent catalyst is atatmospheric pressure. In a second embodiment, at a pressure from 0 to 10psig. In one embodiment, the drying is done under an inert condition,e.g. nitrogen, at a nitrogen flow ranging from 0.2 to 5 scf/min. In oneembodiment, the nitrogen flow ranges from 0.5 to 2 scf/min. Othergeneral conditions, i.e., temperature and residence time, can be varied,accordingly for organic matters to be evaporated from the catalyst. Inone embodiment, the residence time in the drying apparatus ranges from 5minutes to 240 minutes. In a second embodiment, from 10 to 120 minutes.In a third embodiment, at least 15 minutes. In a fourth embodiment, inthe range of 30-60 minutes. With respect to the treatment temperature,it can be varied according to the type of apparatus used, the appliedpressure and the level of heavy oil and solvent remaining in the spentcatalyst. In one embodiment with the use of a vertical thin-film dryer,the temperature is generally in the range of 300 to 450° F. (149 to 232°C.). In a second embodiment with the use of a horizontal thin-filmdryer, the temperature is in the range of 400-700° F. (204 to 371° C.).In a third embodiment with the use of rotary kiln dryer, the temperatureis in the range of 700 to 1200° F. (371 to 649° C.).

In one embodiment, the drying temperature is at a sufficiently hightemperature to decompose at least 90% of the surface active compoundsand/or precursors thereof (collectively referred as “surface activecompounds”), that may be bound to the catalyst particles. In anotherembodiment at least 95% of the surface active compounds thereof areremoved with the use of the dryer.

In one embodiment, the surface active compounds are any of polar organiccompounds, non-polar organic compounds, organo-metallic complexes,inorganic compounds and combinations thereof. In one embodiment, thecompounds are surface active hydrocarbon compounds, comprisingcarboxylates.

In one embodiment, the drying step involves at least a two-stage dryingprocess, with the 2^(nd) drying stage is for the removal ofcontaminants, e.g., carboxylates, residual oil in the pore space of thespent catalyst, etc., volatilizing the organic compounds for removal. Inone embodiment, the retentate stream from the deoiling zone containinghighly concentrated spent catalyst in solvent is first fed into a rotarydrum dryer (operating at a temperature of less than 200° C.) beforegoing into a rotary kiln dryer (operating at a temperature greater than300° C.), with a rotation ranging from 0.5 to 10 rpm and a retentiontime ranging from 5 to 200 minutes. The feed rate to the kiln is basedon the diameter of the kiln. In one embodiment with the use of a 6″diameter kiln, the feed rate to the kiln ranges from 2 to 10 lbs. ofsolid per hour. In another embodiment with a 18″ kiln, the feed rateranges from 10 to 300 lbs. of solid materials per hour.

In yet another embodiment, the retentate stream is first dried in aCombi dryer with an operating temperature in the range of 200 to 450° F.(93 to 232° C.) in the vertical section, a temperature in the range of400-900° F. (204 to 482° C.) in the first half of the horizontalsection, and with a temperature in the last half of the horizontalsection (or the cooling section) in the range of 50-100° F. (10 to 38°C.). Temperature of the stream exiting the Combi drier in one embodimentranges from 80 to 120° F. (27-49° C.).

In one embodiment, the drying zone comprises a plurality of dryingapparatuses to maximize the removal of contaminants, e.g., carboxyl/tea,residual oil in the pore space of the spent catalyst, etc. In oneembodiment, the retentate stream from the deoiling zone is first fedinto a Combi dryer, wherein most of the solvent is removed, for an exitstream consisting essentially of catalyst (as a dry powder) and residualheavy oil (ranging from 0.1 to 1 wt. % in one embodiment, and less than0.5 wt. % in a second embodiment). The Combi dryer in one embodiment ismaintained under a blanket of nitrogen, with nitrogen provided as acounter-current flow in an amount ranging from 0.2 to 5 scf/min. Thisdry powder in next sent to a 2^(nd) drying stage in a rotary kiln dryer,wherein residual organic materials, e.g., heavy oil, is burnt off. Inthe rotary kiln, nitrogen can be supplied as co-current orcounter-current flow. The residence time in the 2^(nd) stage ranges from10 to 150 minutes in one embodiment.

The volatized organic compounds after leaving the catalyst particles canbe collected in condensers, wherein the heavy oil and/or solvents can berecovered.

Detergent Washing: In one embodiment, instead of or in addition to adrying unit for the removal of solvent/residual heavy oil in thecatalyst (after membrane filtration), a surfactant is used to removesolvent and/or heavy oil bound to the catalyst. The surfactant solutionis added to the retentate stream out of the membrane filtration unit. Inanother embodiment, the surfactant solution is added to the streamcontaining catalyst particles and hydrocarbons, i.e., solvent plusresidual heavy oil, out of the drying zone.

In a vessel, e.g., a mixing tank with mechanical agitation, thesurfactant attracts solvent/any residual heavy oil away from the spentsolid catalyst with its hydrophilic head that is attracted to watermolecules and hydrophobic tail that repels water and attaches itself tothe solvent and heavy oil. The opposing forces loosen/remove the solventand heavy oil from the solid catalyst. The mixing of the cleaningsolution containing surfactants and the mixture of spent catalyst andhydrocarbons is for a sufficient amount of time and under conditionssufficient to remove the hydrocarbons from the catalyst surface into theaqueous solution. The mixture of surfactant/solvent/heavy oil in watercan be subsequently separated from the solid catalyst through separationmeans known in the art, including but not limited to decantation and theuse of settling tanks.

In one embodiment, the mixing temperature is in the range of about 30°C. to 85° C. In a second embodiment, the mixing is at a temperature ofless than 85° C. In a third embodiment, at a temperature of up to 177°C. In one embodiment, the mixing (contacting) of the cleaning solutionand the mixture of spent catalyst and hydrocarbons is for at least twominutes. In a second embodiment, for at least 5 minutes. In a thirdembodiment, for at least 10 minutes.

In one embodiment, the surfactant is first dissolved in water, e.g.,deionized water, in a concentration between about 0.001% and saturation.In a second embodiment, the surfactant is added in a concentrationbetween 0.01% to about 10%, in a third embodiment, at a concentrationbetween 0.5% to about 5%. In a fourth embodiment, at a concentrationsufficient to dissolve and remove at least 90 wt. % of the hydrocarbons,i.e., solvents and heavy oil, from the surface of the catalystparticles. In a fifth embodiment, the concentration of the surfactant issufficient to dissolve and remove at least 95 wt. % of the hydrocarbonsfrom the catalyst particles.

In one embodiment, the surfactant is selected from the group of anionic,nonionic, zwitterionic, acidic, basic, amphoteric, enzymatic, andwater-soluble cationic detergents and mixtures thereof. In oneembodiment, the surfactant is an anionic detergent.

In one embodiment, the detergent is an anionic surfactant selected fromwater-soluble salts, particularly the alkali metal, ammonium andalkanolammonium salts, of organic sulfuric reaction products having intheir molecular structure an alkyl group containing from about 8 toabout 22 carbon atoms and a sulfonic acid or sulfuric acid ester group.(Included in the term “alkyl” is the alkyl portion of acyl groups.)Examples of this group of synthetic surfactants include sodium andpotassium alkyl sulfates, especially those obtained by sulfating thehigher alcohols (C₈-C₁₈ carbon atoms) produced by reducing theglycerides of tallow or coconut oil, sodium and potassium C₈-C₂₀paraffin sulfonates, and sodium and potassium alkyl benzene sulfonates,in which the alkyl group contains from about 9 to about 15 carbon atomsin straight chain or branched chain configuration.

In another embodiment, the anionic surfactant compound is selected fromthe group of sodium alkyl glyceryl ether sulfonates, and sodium orpotassium salts of alkyl phenol ethylene oxide ether sulfate containingabout 1 to about 10 units of ethylene oxide per molecule and wherein thealkyl groups contain about 8 to about 12 atoms. In yet anotherembodiment, the anionic surfactant is selected from sodium linearC₁₀-C₁₂ alkyl benzene sulfonate; triethanolamine C₁₀-C₁₂ alkyl benzenesulfonate; sodium tallow alkyl sulfate; sodium coconut alkyl glycerylether sulfonate; and the sodium salt of a sulfated condensation productof tallow alcohol with from about 3 to about 10 moles of ethylene oxide;mixtures of sodium and potassium alkyl sulfates

In one embodiment, the surfactant is a nonionic surfactant. Examplesinclude the water-soluble ethoxylates of C₁₀-C₂₀ aliphatic alcohols andC₆-C₁₂ alkyl phenols.

In one embodiment, the surfactant is a semipolar surfactant. Examplesinclude water-soluble amine oxides containing one alkyl moiety of fromabout 10 to 28 carbon atoms and 2 moieties selected from the groupconsisting from 1 to about 3 carbon atoms; water-soluble phosphineoxides containing one alkyl moiety of about 10 to 28 carbon atoms and 2moieties selected from the group consisting of alkyl groups andhydroxyalkyl groups containing from about 1 to 3 carbon atoms; andwater-soluble sulfoxides containing one alkyl moiety of from about 10 to28 carbon atoms and a moiety selected from the group consisting of alkyland hydroxyalkyl moieties of from 1 to 3 carbon atoms.

In one embodiment, the surfactant is an amholytic surfactant. Examplesinclude derivatives of aliphatic or aliphatic derivatives ofheterocyclic secondary and tertiary amines in which the aliphatic moietycan be straight chain or branched and wherein one of the aliphaticsubstituents contains from about 8 to 18 carbon atoms and at least onealiphatic substituent contains an anionic water-solubilizing group.

In yet another embodiment, the surfactant is a zwitterionic surfactant.Examples include derivatives of aliphatic quaternary ammonium,phosphonium and sulfonium compounds in which the aliphatic moieties canbe straight or branched chain, and wherein one of the aliphaticsubstituents contains from about 8 to 18 carbon atoms and one containsan anionic water-solubilizing group.

It is further envisaged to use common surfactants including but notlimited to vegetable derived surfactants; household detergents includingnatural oils such as orange oils, citrus oils, etc.; commerciallyavailable degreasers; and common laboratory surfactants and detergents,e.g., alkyl sulphates, alkyl ethoxylate sulphates. In one embodiment,the surfactant is sodium laureth sulfide (SDS), Brij detergents andniaproff anionic detergents. In another embodiment, the anionicdetergent is a proprietary blend of sodium linear alkylaryl sulfonate,alcohol sulfate, phosphates and carbonates commercially available asknown as ALCONOX™. In yet another embodiment, the surfactant is acommercially known detergent by the name of LIQUINOX™.

It is further envisaged that surfactants do not have to be added as acleaning solution. In one embodiment, the surfactant solution isgenerated in-situ with the addition of precursor materials, e.g., alkalimetal compounds such as sodium hydroxide, ammonium hydroxides, etc.,such that at least a surfactant is generated in-situ for use in thedetergent washing process.

Ultrasonic Cleaning: In one embodiment, instead of or in addition to theuse of detergent for the cleaning/removal of solvent and heavy oil fromthe spent catalyst, ultrasonic cleaning is employed. Ultrasonic cleaningherein involves the use of high-frequency sound waves (above the upperrange of human hearing, or about 18 kHz). In one embodiment, ultrasonictransducers are employed with a frequency ranging from 20 to 80 kHz. Ina third embodiment, the frequency employs ranges from 15-400 kHz. Theultrasonic tank in one embodiment is maintained at a temperature of atleast 50° C. in one embodiment, and at least 70° C. in a secondembodiment, up to a temperature of at least 6° C. below the boilingpoint of the solvent still remaining with the spent catalyst.

In one embodiment, ultrasonic/acoustic energy is applied to the cleaningsolution for less than 15 minutes. In one embodiment, from 0.25 to 10minutes. In a third embodiment, for less than 60 minutes. In oneembodiment the organic components such as solvent and heavy oil attachedto the catalyst particles are fully dislodged from the surfaces with theimplosion of the bubbles initiated by the ultrasonic energy. In asubsequent separation process, e.g., a cyclone, a decanter or settlingtank, the deoiled fine catalyst particles can be separated and collectedfrom the bottom. The aqueous phase containing solvent and heavy oil canbe sent to a water treatment apparatus, wherein the fraction enrich withorganic matters can be recovered and water can be recirculated as cleanwater to the detergent washing process. It is also possible to clean thewaste water by ultrafiltration, adsorption column or other means beforeit is reused as wash water in the detergent washing process.

Plasma Cleaning: In one embodiment, instead of or in addition toultrasonic cleaning or using at least a surfactant for thecleaning/removal of solvent and heavy oil from the spent catalyst,plasma cleaning is employed. In some embodiments, it is advantageous touse a plasma system as compared to a convention dryer is that a typicalplasma jet is at much higher temperature than a typical oil or gasburner. Therefore the heat transfer, dependent on the temperatures ofthe energy source and the heated substance, can be higher in a plasmaprocess, increasing the energy efficiency of the plasma process.

In one embodiment, the plasma cleaning process operates at a temperaturebetween 400 to 900° C. (752 to 1652° F.) in order to volatize theresidual hydrocarbons, i.e., heavy oil residues and solvent, in thecatalyst particles. The volatized organic compounds after leaving thecatalyst particles can be collected in condensers, wherein the heavy oiland/or solvents can be recovered. The plasma reactor/vessel can bemaintained under an inert blanket or reducing atmosphere to allow therecovery of the organic materials after volatilizing them in the plasmareactor as effluent gases, leaving behind the catalyst particles as drypowder containing less than 0.5 wt. % hydrocarbons as solvent materialsand/or residual heavy oil.

In one embodiment, the plasma cleaning system comprises a vessel (e.g.,a mixing tank or a reactor), a plasma system for heating the mixture ofcatalyst particles and hydrocarbons within the vessel, and means forcollecting the effluent gases. In one embodiment, the plasma systemcomprises graphite electrodes and electric arcs maintained between thegraphite electrodes. In another embodiment, the plasma system comprisesa plurality of plasma torches located within the vessel reactor. In oneembodiment, a condenser system is employed to collect and recover thevolatized hydrocarbons. In yet another embodiment, a splitter column isemployed to collect and separate solvents from residual heavy oils inthe volatized hydrocarbons collected from the plasma system.

Reference will be made to the figures to further illustrate embodimentsof the invention.

In one embodiment of a deoiling zone as illustrated in FIG. 4, feedstockstream 1 to deoiling zone 200 enters slurry drum 100 where feedstock 1is stored and continuously mixed by slurry pump 150. Feedstock 1 leavesslurry drum 100 via line 2 and passes to slurry pump 150, which pumpsfeedstock 1 up to the operating pressure of deoiling zone 200. A portionof the feedstock in line 2 is recycled to slurry drum 100 through line 3to agitate the feedstock and prevent agglomeration of the catalystparticles in slurry drum 100. A main portion of the feedstock in line 2continues to deoiling zone 200, but just before entering deoiling zone200, feedstock 1 is mixed with a light hydrocarbon solvent 4, threxample, a toluene rich stream, to dilute the unconverted residhydrocarbon oil and form stream 5, which is fed to deoiling zone 200.

In one embodiment, the light hydrocarbon solvent 4 is toluene. Indeoiling zone 200, unconverted oil is removed from the catalystparticles of stream 5, leaving stream 6 consisting essentially ofunconverted oil in the light hydrocarbon solvent, e.g., toluene. Stream6 is sent to heat exchanger 250 to form heated stream 7, which entersseparator 300 where flashed off overhead is toluene vapor stream 8 andunconverted oil is removed as stream 9. In an embodiment, separator 300is a distillation column, in order to achieve a sharp separation betweensolvent and recovered oil. Stream 9 comprising unconverted oil can berecycled to the heavy oil upgrade process, e.g., a vacuum resid unit,thr further processing or sent to product storage. Stream 14 from thedeoiling zone 200 consists of catalyst particles, carbon fines, andmetal fines less stream 6 consisting of unconverted oil in toluene.Stream 14 proceeds to drying zone 500 where toluene vapor stream 16 isseparated from catalyst, carbon fines, and metal fines (i.e.,hydrocarbon-free solids) in stream 17. The drying zone can beevaporation and solids devolatilization equipment known to those skilledin the art. In one embodiment (not shown), stream 17 is routed to ametal recovery system wherein the metals in the catalyst can berecovered and subsequently used in a catalyst synthesis unit.

Toluene vapor streams 8 and 16 are combined into composite toluene vaporstream 31, which enters condensing unit 350 where the toluene isconverted from a vapor state to a liquid state and leaves the condensingunit as liquid toluene stream 11. Liquid toluene stream 11 enterssolvent storage drum 400, from which toluene is recycled to the deoilingzone 200 via line 13. Make-up toluene stream 12 is added to solventstorage drum 400, since a small amount of toluene is lost throughvaporization.

In yet another embodiment of a deoiling system as illustrated in FIG. 5,stream 11 from the deoiling zone 200, consisting of catalyst particles,carbon fines, and metal fines less stream 6, can be sent to slurryconcentration zone 550, from which a portion of stream 14 (stream 19) isfed to drying zone 500 and a portion of stream 14 is fed via line 18 tobe mixed into toluene vapor stream 16 from drying zone 500.

In another embodiment as illustrated, in FIG. 6, before the feedstockstream (containing spent catalyst in heavy oil) 1 is mixed with lighthydrocarbon solvent 4, line 2 can be fed to slurry concentration zone600, from which unconverted oil 21 is removed. Stream 22 (i.e.,feedstock 1 less unconverted oil 21) is then be mixed with lighthydrocarbon solvent 4 and fed to deoiling zone 200.

FIG. 7 illustrates the deoiling system as illustrated in FIG. 2, whichfurther contains a slurry concentration zone 550 (as illustrated in FIG.5) and the slurry concentration zone 600 of FIG. 6.

With reference to FIG. 8, feedstock 51 is mixed with light hydrocarbonsolvent 54 to form stream 55, which is fed to a first filtration unitconsisting of membrane 215 separating top section 210A and bottomsection 210B. Typically, stream 55 enters the tube side of a multi-tubebundle of membrane elements with the permeate stream 56 exiting theshell side of the membrane housing. In the description that follows,light hydrocarbon solvent 54 is a toluene rich stream (i.e., permeatefrom the second stage of filtration). Slurry pump 230 maintains aconstant velocity in the tubes, preventing settling or agglomeration ofcatalyst particles. A portion of unconverted oil along with toluenepasses through membrane 215 to bottom section 210B and out of the firstfiltration unit as stream 56 and can be sent to a distillation processto recover toluene and unconverted oil as separate streams. Retentatestream 57 is diluted with a toluene rich stream 58 to form stream 59,which is passed to a second filtration unit. The second filtration unitconsists of membrane 225 separating top section 220A and bottom section220B. Slurry pump 240 maintains a constant velocity in top portion 220Aabove membrane 225 and keeps stream 59 in continuous motion, preventingsettling or agglomeration of catalyst particles. A portion ofunconverted oil along with toluene passes through membrane 225 to bottomsection 220B and out of the second filtration unit as stream 54, whichis recycled to be mixed with feedstock 51 to form stream 55.

FIG. 9 illustrates an embodiment of a deoiling zone with the use of asettling tank system 70 for pre-mixing/washing of the catalyst slurryfrom a heavy oil upgrade system. Solvent feed to the settling tank canbe recycled solvent from any of the drying zone 20 or the solventrecovery system 50. In one embodiment, a portion (or all) of thefiltrate from the filtration unit is recycled back to the settling tank70 as shown. In another embodiment, a portion (or all) of the retentateis recycled back to the settling tank 70 as shown. In yet anotherembodiment (not shown), recycled solvent from the recycling zone canalso be diverted to the settling tank for use in washing the feed streamcomprising slurry catalyst in heavy oil.

FIG. 10 illustrates an embodiment of a system with a two-staged dryingzone. The first drying zone can be any of a rotary dryer, a verticalthin-film dryer, a horizontal thin-film dryer, or a Combi dryer(combination of both vertical and horizontal). As shown, the filtratefrom the membrane filtration unit comprising solvent and heavy oil ispassed on to a solvent recovery unit. In this unit, the solvent iscondensed into a liquid stream and passed on to a solvent tank. In oneembodiment, the solvent recovery unit comprises a distillation column toachieve a sharp separation between solvent and heavy oil. Heavy oil canbe recycled to a vacuum resid unit for further processing or sent toproduct storage. In the 1^(st) drying stage 20, a retentate stream 2from the filtration unit is substantially concentrated, e.g., for astream containing less than 0.2 wt. % heavy oil, up to 90 wt. % solventand the remainder solid catalyst to transform into substantially drypowder form, with up to 1 wt. % heavy oil. Solvent vapor stream can berecovered (condensed) and recycled back to the membrane filtration unitor a settling tank (not shown) for mixing with the feed stream to thefiltration unit.

In the 2^(nd) drying stage, e.g., a rotary kiln dryer, organic mattersare substantially evaporated for a stream consisting essentially of dryspent catalyst powder including metal and carbon fines.

Metal Recovery from Dry Powder Catalyst: In one embodiment, the dryspent catalyst powder is sent to a metal recovery unit for recovery ofvaluable metals such as molybdenum, nickel, chromium, etc. forsubsequent re-use in a catalyst synthesis unit. In one embodiment, thedeoiled and dried spent catalyst particles first leached with an aqueoussolution containing ammonia and air in an autoclave, i.e., amulti-chambered, agitated vessel at a sufficient temperature andpressure, in which ammonia and air are supplied to induce leachingreactions, wherein the group VIB (e.g., molybdenum) and group VIIImetals (e.g., nickel) are leached into solution forming group VIB andgroup VIII soluble metal complexes.

The leached slurry is subsequently subject to liquid-solid separationvia physical methods known in the art, e.g., settling, centrifugation,decantation, or filtration, and the like, into a liquid streamcontaining the group VIB and VIII metal complexes (“PLS” or pressureleached solution) and a solid residue comprising coke and any group VBmetal (vanadium) complex. Following liquid-solid separation, the pH ofthe PLS stream controlled to a level at which selective precipitation ofthe metal complexes occurs (“pre-selected pH”), allowing theprecipitation of at least 90% of the Group VIB metal, at least 90% ofthe Group VIII metal, and at least 40% of the Group VB metal initiallypresent prior to the precipitation. In one embodiment, the metalcomplexes undergo further treatment/pre-selective pH conditioning tofurther recover the Group VIB and Group VIII metals as metal sulfides,which can be subsequently used in a catalyst synthesis unit.

EXAMPLES

The following illustrative examples are intended to be non-limiting.

Cross-flow Filtration Example. A feedstock of used resid hydroprocessingslurry phase catalyst (1 to 10 μm) in unconverted heavy oil product wasprocessed using eight stages of cross-flow filtration. The cross-flowfiltration was conducted at 175° C. and 75 psig. The feed slurry solidscontent was 12 weight %. In each stage the feed oil was diluted with anamount of toluene equal to the original feed slurry. The resultingmixture was circulated through the cross-flow filtration module untilsufficient oil and toluene permeated through the membrane to create areconcentrated slurry of 25 weight % solids. A recirculating pumpmaintained a sufficient velocity through the tubes of the filter housing(greater than 10 feet/second) to avoid membrane fouling.

The design of the membrane was such that only the oil could permeatethrough the walls of the tube into the shell side of the bundle whilethe fine solid catalyst was retained on the tube side. By repeating thisprocess an additional seven times the catalyst was transferred into asubstantially oil-free toluene stream. The resulting toluene slurry wasevaporated in a combination vertical thin film/horizontal dryer toproduce a dry solid. The hottest zone in the dryer was operated at atemperature of 550° F. Analysis of the dry solid gave less than 0.5weight % toluene extractable oil, which indicates over 99.9% oilremoval. This material was found to sufficiently deoiled to allowrecovery of the active metals using a water based leaching process. Ananalysis of the permeate oil stream showed no detectible level ofmolybdenum, which provides confirmation that the molybdenum basedcatalyst was quantitatively recovered into the clean toluene slurry.

The single stage cross-flow filtration membrane module run eight timesin sequence simulated an eight stage cross-flow system. However, a verylarge amount (7.75 times the fresh slurry rate) of toluene was usedsince each stage was cross-flow and a very high deoiling extent wastargeted. In an embodiment, toluene is added only to the last stage andthe toluene permeate cascades to the prior stage, requiring perhaps 5 or6 stages (and a toluene rate of 2-3 times the fresh slurry rate).

Dynamic Filtration Example. Catalyst in oil exchanged with toluene wastested at 100° C. (temperature correction base). Twenty gallons of acatalyst/oil slurry feed were tested. First, the solids wereconcentrated in oil and then the solids were washed or diafiltered inoil slurry using toluene as the wash solvent (i.e., the oil wasexchanged with solvent). The pumpable catalyst/oil slurry contained 14weight % catalyst solids and other solids and 86 weight % oil. In anembodiment, the oil is removed and replaced by toluene until the oilconcentration is less than about 2 weight %.

Specifically, toluene was used as a replacement solvent to displace theoil and keep the total solids at a pumpable level. Any permeatecontaining oil or toluene can be sent to a distillation column forrecovery. The final washed catalyst solids can be further treated usinganother technology. Only oil, toluene, and soluble solids would passthrough the membrane, while catalyst solids would be retained.Accordingly, catalyst slurry in a liquid form with reduced amounts ofoil is produced, which would be suitable for additional treatment steps.In an embodiment, at least about 95 weight % of the solids in the finalwashed concentrate (retentate) is recovered. Heating equipment was usedand a sealed nitrogen purged tank was used to process the feed liquid.

Testing was conducted by isolating as many of the variables as possibleto determine optimum variables. Variables included type of membrane,temperature, pressure, concentration factor, and fouling. Variables weretested as follows.

The sample material was pre-screened using a 100-mesh screen to removelarge particles and then placed into a feed tank connected to a Series LV*SEP Machine from New Logic. The membranes were installed and feed wasintroduced and pumped into the Series V*SEP Machine.

Step 1. Membrane Study. The membrane study was used to evaluate avariety of membranes on the sample material to determine the optimummembrane in terms of flux and/or permeate quality. The performance wasmeasured in “recirculation mode,” meaning that the material was notconcentrated but the separated streams were returned to the feed tankand only the relative performance of each membrane under the sameconditions was measured. A exemplary “recirculation mode” is shown inFIG. 11.

Step 2. Pressure Study. The pressure study was used to determine theoptimum pressure of the chosen membrane on the particular feed material.The permeate rate was measured as incremental increases in pressure weremade to the system. The pressure study determined whether it is possibleto reach a point at which increased pressure does not yield significantincrease in permeate flow rate, and at what pressure increasing pressurefurther does not yield significant increase in permeate flow rate.

Step 3. Long Term Line-Out Study The long term line-out study was usedto measure the flux versus time to determine if the permeate rate isstable over a period of a time. The long term line-out study was anextended test to verify whether the system will lose flux, as do tubularcross flow systems. The results of the long term line-out study can alsobe used to determine a cleaning frequency, if one is necessary.

Step 4. Washing Study The washing study was designed to measure fluxversus wash volume in order to evaluate an average flux over eachindividual washing. The washing study was completed in batch mode, asthe membrane area of the Series L V*SEP Machine was only 0.5 ft2.Permeate was continually removed from the system while the concentratedmaterial was returned to the feed tank. The washes were added one at atime and when an equivalent amount of permeate compared to the addedwash water was removed then one wash was complete. For the washingstudy, one continuous wash was completed in batch mode. As permeate wasremoved, additional toluene was added to the tank.

Step 5. Concentration Study The concentration study was designed toconcentrate the solids to a desired endpoint, if not obtained in thewashing study. The concentration study was completed in batch mode, asthe membrane area was only 0.5 ft2. Permeate was continually removedfrom the system while the concentrated material was returned to the feedtank. The resulting data was used to determine the average flux over theconcentration/recovery range, which, in turn, allows for preliminarysystem sizing.

Test conditions included a temperature of about 90-100° C. (temperaturecorrected to 100° C.), a pressure of about 100-120 psi for the membranestudy and 90 psi for the washing study, a sample size of 20 gallons,and, as noted above, a membrane area of 0.5 ft2.

Results—Membrane Selection. Two membranes having good chemicalresistance and that can tolerate high temperature, detailed in Table 1,were selected, for study.

TABLE 1 Membranes Tested Maximum Membrane Type Pore Size TemperatureWater Flux* Teflon ® on Halar ® Microfiltration 0.05 μm 200° C. 500 gfdTeflon ® on Woven Fiberglass Microfiltration  0.1 μm 200° C. 750 gfd*Average Batch Cell Test Results on New Membrane at 60 psi and 20° C.

The relative performance of each of the selected membranes was tested.The feed tank was prepared with the sample feed material and the systemwas configured in “recirculation mode”. Each of the membranes shownabove was installed and a two to four hour “line-out study” wasconducted. The membranes were compared based on flux and permeatequality. Table 2 shows the relative performance of each membrane.

TABLE 2 Results of Membrane Selection Membrane Initial Flow* EndingFlow* Pressure Teflon ® on Halar ® 42.6 ml/min 47.8 ml/min 100 psiTeflon ® on Woven Fiberglass 25.8 ml/min 11.7 ml/min 120 psi*Temperature corrected to 100° C.

FIG. 12 is a graph illustrating the results of the membrane study. Theoperating temperature was 100° C. Factors used to select a membrane mayinclude, for example, flow rate, permeate flux rate, filtrate quality,chemical compatibility of the membrane, mechanical strength of themembrane, and temperature tolerance of the membrane. The 0.05 μm Teflon®membrane had better flux rates than the 0.1 μm Teflon® membrane.Analytical testing results on the filtrate from each showed that the0.05 μm Teflon® membrane had 181 ppm of suspended solids in thefiltrate. While the 0.1 μm Teflon® membrane had only 72 ppm of totalsuspended solids. The feed slurry was 9.18 weight % solids and 90.82weight % oil. Accordingly, the 0.05 μm Teflon® membrane provided abetter flow rate but worse permeate quality.

In addition to an excellent flow rate of permeate quality, the membranemust be durable and able to stand up to the feed material. Manymaterials are available for membrane construction, which remains anavailable optimizing technique. In addition to the membrane itself, allof the other wetted parts should be examined for compatibility. BothHalar® (ethylene chlorotrifluoro-ethylene) and woven fiberglass materialchemically inert and would be compatible with toluene and the oilcarrier. In addition, both would be capable of tolerating the 100° C.process temperature. The membranes are essentially equivalent in termsof chemical compatibility and temperature tolerance criteria.

However, in terms of mechanical strength of the membranes, wovenfiberglass backing material is much stronger and would hold up betterover the long term than Halar®. Accordingly, the 0.1 μm Teflon® membraneon woven fiberglass was chosen for further analysis.

Pressure Selection. The results of the pressure study are shown in FIG.13. The operating temperature was 100° C. An optimum pressure wasdetermined by measuring the flux at various pressures. The greatest fluxoccurred at 90 psi, giving an optimum pressure of 90 psi.

Initial Concentration. The system was started up first in “recirculationmode” and set to the optimum pressure and expected process temperature.The system was run for a few hours to verify that the flux was stableand the system has reached equilibrium.

The permeate line was then diverted to a separate container so thesystem was operating in “batch” mode. The permeate flow rate wasmeasured at timed intervals to determine flow rate produced by thesystem at various levels of concentration. As permeate was removed fromthe system, the solids concentration rose in the feed tank. FIG. 14illustrates a batch mode operation.

Initial concentration allows for reduction of the volume of the feed byremoving oil and concentrating the solids. As a result, it is possibleto use less volume of wash solvent. No wash solvent has been added andonly the initial solids are concentrated.

Table 3 shows the mass balance results of the initial concentration.

TABLE 3 Mass Balance Results Initial Ending % Initial % Ending % VolumeVolume Recovery Solids Solids 20 gallons 11.7 gallons 41.49% 9.18%15.69%

The initial concentration was done at about 100° C. and a pressure ofabout 90 psi. While further concentration could have been performed,after the initial concentration the feed was very viscous and the fluxrates were relatively low due to the viscosity. It was believed that theaddition of toluene would cut the viscosity and greatly improve the fluxrate. Concentrating was stopped at about 41% recovery, since asignificant volume reduction had taken place, the percentage of solidshad risen to a respectable level, and flow rates could be improved withtoluene addition.

Table 4 shows system performance during the initial concentration.

TABLE 4 Initial Concentration Results Initial Flux Ending Flux AverageFlux Pressure Temperature 34.5 gfd 28.2 gfd 29.6 gfd 90 psi 100° C.

Diafiltration Process. Once the feed had been volume reduced by 41% andabout 11.7 gallons of feed remained, the system configuration waspreserved with permeate being diverted to a separate container and thereject line being returned to the feed lank. Also, clean toluene wasadded to the feed tank in a topped off fashion to maintain the tanklevel and replenish the feed volume as filtrate was removed.

Processing continued for several days. During the washing study, ninesmall samples were taken of the permeate and concentrate at differenttimes throughout the washing study. After about 75 gallons of wassolvent had been added, the washing process was stopped. Initially, thefiltrate was very dark and oily. As the wash process continued, thefiltrate became lighter in color until the color was a very light amber.Table 5 shows the mass balance results during the diafiltration.

TABLE 5 Diafiltration Mass Balance Results Filtrate Wash Permeate RejectID Time Removed Volume Solids Solids 1  165 min  1.8 gal 0.1×   1 ppm 9.77% 2  301 min  3.1 gal 0.3×   3 ppm  9.88% 3  906 min 10.3 gal 1.0× 153 ppm  4.62%  3a 1117 min 12.5 gal 1.3×   4 ppm 11.31% 4 2362 min38.3 gal 4.0× 1500 ppm  7.86% 5 2974 min 58.0 gal 5.7×  406 ppm 24.51% 63122 min 61.1 gal 5.9×  481 ppm 41.33% 7 3180 min 61.9 gal 6.0×  137 ppm38.58% 8 3430 min 71.9 gal 6.9×  21 ppm 25.01% 9 3983 min 80.3 gal 7.6× 32 ppm 42.41%

Prior to testing, it was estimated that six wash volumes would be enoughto theoretically “clean” the solids and remove enough oil. During thecourse of testing, about 75 gallons of clean toluene were used.Diafiltration was stopped after the supply of toluene was exhausted andafter more than six wash volumes had been completed. The ending volumewas concentrated until the feed slurry was reasonably thick.Concentration was stopped when the slurry was quite thick and thereexisted a risk of plugging.

FIG. 15 is a graph of the diafiltration study. Process conditionsincluded a temperature of 100° C., a pressure of 90 psi, and the Teflon®on woven fiberglass membrane with 0.1 μm pore size. The average fluxplot includes data from the initial concentration, not shown in thegraph. The actual average flux during testing was 112 gfd.

During testing several observations were made: 1) non-woven fiberglassdrain cloth (“Manniglass”) did not hold up mechanically; 2) nylon“Tricot” drain cloth did hold up well; 3) polypropylene drain clothworked acceptably but swelled; 4) when the system sat idle, solids wouldsettle in the piping and plug the system; 5) good pre-screening isneeded to catch agglomerations; 6) no significant H2S was present in thesample (300 ppm was present initially but removed); 7) flux rates werelow on oil, but improved greatly once toluene was added; 8) Viton®elastomers swelled badly and failed several times; 9) low cross-flowallowed accumulation of solids in the filter head; and 10) a cake layerbuilt up on the membrane surface.

As mentioned above, at first, the filtrate was dark colored, althoughnot turbid. Toward the end of the diafiltration, the color changed to alight amber color. During testing, there were several instances wherethe filter head was disassembled to replace leaking Viton® seals andfailed drain cloth materials. Each time the filter head was opened, thepermeate chamber was contaminated with the feed slurry. Upon resumptionof operation, the filtrate would exhibit some turbidity initially, andthen would clear up as the contamination cleared. Large variations wereobserved in the percentage of solids in the filtrate. Without wishing tobe bound by theory, it is believed that the large variations wereobserved in the percentage of solids in the filtrate can be explained bypermeate chamber contamination.

Table 6 shows the permeate quality after a membrane change.

Table 6 Diafiltration Time Results ID Total Time Delta Time PermeateSolids 2313 min   0 min Membrane Change 4 2362 min  49 min 1500 ppm 2792min   0 min Membrane Change 5 2974 min  182 min  406 ppm 6 3122 min  330min  481 ppm 7 3180 min  388 min  137 ppm 8 3430 min  638 min  21 ppm 93983 min 1191 min  32 ppm

The membrane itself should be able to hold back a significant percentageof solids. Solids in the permeate may not be a result of solids passingthrough membrane pores. Rather, contamination might have contributed tosolids in the filtrate. In addition, swelled Viton® o-rings might havebeen providing, at best, a marginal seal. Each time the membrane waschanged a new set of o-rings was installed. With no contamination of thepermeate chamber and with good o-ring seals, the solids in the filtratemight be in the range of about 10-20 ppm.

Another possible explanation for the solids in the filtrate is thedistribution of pore sizes in the membrane. In particular, whilemembranes have nominal pore size ratings, the actual pore sizes in anygiven membrane vary. The pore size distribution curve is shaped like abell curve. The nominal pore size rating is normally the mean of all thesizes. Thus, a membrane with a nominal pore size rating of 0.1 μm canhave pores as large as 1.0 μm. Examining the particle size distributionof the catalyst solids, there could be some overlap, as shown in FIG.16.

Teflon® membranes rated at 0.05 μm, or smaller, might even be too largeto completely remove all solids. While smaller membranes, with poresizes down to 0.01 μm, made of other materials including polyvinylidenedifluoride (PVDF; Kynar®), might have better solids removal capability,such membranes might have lower chemical and temperature tolerance andbe less durable over time.

System with Integrated Cross-flow Filtration & Combi Drying Units: Aslurry feed stream (100 lbs/hr) from a heavy oil upgrading unit isprovided. The stream contains 20 lbs, of spent catalyst in 80 lbs. ofheavy oil with the heavy oil being unconverted heavy oil/heavierhydrocracked products. About 300 lbs. of solvent is also provided to thecross-flow filtration unit. The cross-flow filtration unit has aplurality of filter stages with operating conditions as shown in Table7:

Filter stage Temperature (° F.) Pressure (psig) 1 200  30 2 200  50 3200  70 4 200  90 5 200 110

The retentate stream (100 lbs) from the cross-flow filtration unitcomprises 20 wt. % spent catalyst, 79.9 wt. % of a solvent such astoluene, and 0.1 wt. % heavy oil is sent to a drying zone connected inseries. The filtrate stream contains approximately 220.1 lbs. solventand 79.9 heavy oil is sent to a solvent recovery unit.

The drying apparatus used in the 1^(st) stage of the drying zone is anLCI Combi Dryer heated indirectly by either steam or hot oil, with anoperation temperature of 232° F. in the vertical section, the first halfof the horizontal section operating at approximately 800° F. and thelast half of the horizontal section (or the cooling section) is between70 to 77° F. The Combi dryer is maintained, at a pressure ranging from 0to 10 psig, with a counter-current nitrogen flow maintained in the rangeof 0.5 to 1 scf/min. Dry powder catalyst exiting the Combi dryer at atemperature ranging from 100 to 110° F. and with a retention time in theequipment of 10 to 120 minutes. TGA (thermogravimetric analysis) is usedto measure the oil content in the dry catalyst powder, showing a heavyoil concentration of less than 0.5 wt. %.

System with Cross-flow Filtration & Two-Stages Drying Units: Theprevious example is repeated with the addition of a rotary kiln dryer inseries with the Combi dryer. The dry powder from the Combi unit is sentto a rotary kiln dryer at a rate ranging from 4 to 6 lbs. per hour. Thekiln operates temperature of about 800° F., having a kiln rotation from1 to 5 rpm, and a retention time ranging from 30 to 60 minutes. Nitrogenflow is co-current in the rotary kiln. TGA analysis shows a oilconcentration in the powder exiting the kiln of less than 0.1 wt %, andat an amount of less than 0.05 wt %, in one embodiment.

For the purposes of this specification and appended claims, unlessotherwise indicated, all numbers expressing quantities, percentages orproportions, and other numerical values used in the specification andclaims, are to be understood as being modified in all instances by theterm “about.” Accordingly, unless indicated to the contrary, thenumerical parameters set forth in the following specification andattached claims are approximations that can vary depending upon thedesired properties sought to be obtained by the present invention. It isnoted that, as used in this specification and the appended claims, thesingular forms “a,” “an,” and “the,” include plural references unlessexpressly and unequivocally limited to one referent. As used herein, theterm “include” and its grammatical variants are intended to benon-limiting, such that recitation of items in a list is not to theexclusion of other like items that can be substituted or added to thelisted items.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to make and use the invention. The patentable scope is defined bythe claims, and can include other examples that occur to those skilledin the art. Such other examples are intended to be within the scope ofthe claims if they have structural elements that do not differ from theliteral language of the claims, or if they include equivalent structuralelements with insubstantial differences from the literal languages ofthe claims. All citations referred herein are expressly incorporatedherein by reference.

1. A system for removing hydrocarbons including solvents and heavy oilfrom catalyst particulate from a composition containing catalystparticles in 50 to 90 wt. % hydrocarbons, the system comprising: adrying zone comprising at least two drying apparatuses, with the seconddrying apparatus being operated at a sufficiently high temperature forvolatizing at least 90% of hydrocarbons from the catalyst particles; andmeans for collecting and recovering the volatized hydrocarbons.
 2. Thesystem of claim 1, wherein the first drying apparatus is selected, froman indirect fired kiln, an indirect fired rotary kiln, an indirect fireddryer, an indirect fired rotary dryer, an electrically heated kiln, anelectrically heated rotary kiln, a microwave heated kiln, a microwaveheated, rotary kiln, a vacuum dryer, a thin film dryer, a flexicoker, afluid bed dryer, a shaft kiln dryer, a thin film dryer, a thin-filmevaporator, a wiped film dryer, and a wiped-film evaporator.
 3. Thesystem of claim 1, wherein the first drying apparatus is a vertical thinfilm dryer.
 4. The system of claim 1, wherein the first drying apparatusis a horizontal thin film dryer.
 5. The system of claim 1, wherein thefirst drying apparatus is a thin film dryer having a combined designwith a first vertical section and a second horizontal section.
 6. Thesystem of claim 5, wherein the vertical section operates at atemperature ranging from 200 to 450° F. and the horizontal sectionoperates at a temperature ranging from 50-100° F.
 7. The system of claim1, wherein the second drying apparatus is for removing surface activecompounds bound onto the catalyst particles.
 8. The system of claim 1,wherein the second drying apparatus is a rotary kiln dryer.
 9. Thesystem of claim 8, wherein the rotary kiln dryer is operated at atemperature ranging from 700 to 1200° F.
 10. The system of claim 8,wherein the rotary kiln dryer is operated at a temperature sufficientlyhigh to volatize surface active compounds bound onto the catalystparticles and reduce the hydrocarbons in the catalyst particles to lessthan 0.5 wt. %.
 11. The system of claim 8, wherein a condenser is usedfor collecting and recovering the volatized hydrocarbons.